diff --git a/docs/topics/commands.rst b/docs/topics/commands.rst
index 50da4593a..bbfadc45c 100644
--- a/docs/topics/commands.rst
+++ b/docs/topics/commands.rst
@@ -341,8 +341,8 @@ list
 * Syntax: ``scrapy list``
 * Requires project: *yes*
 
-List all available spiders in the current project. The output is one spider per
-line.
+List all :ref:`spiders <topics-spiders>` available in the current project. The
+output is one spider per line.
 
 Usage example::
 
@@ -350,6 +350,9 @@ Usage example::
     spider1
     spider2
 
+Which spiders are listed depends on the configured
+:setting:`SPIDER_LOADER_CLASS`.
+
 .. command:: edit
 
 edit
diff --git a/docs/topics/settings.rst b/docs/topics/settings.rst
index e58815fad..dd1094db4 100644
--- a/docs/topics/settings.rst
+++ b/docs/topics/settings.rst
@@ -2083,6 +2083,32 @@ The class that will be used for loading spiders, which must implement the
 
 .. note:: This is a :ref:`pre-crawler setting <pre-crawler-settings>`.
 
+.. setting:: SPIDER_LOADER_REQUIRE_NAME
+
+SPIDER_LOADER_REQUIRE_NAME
+--------------------------
+
+Default: ``True``
+
+.. note::
+
+    While the default value is ``True`` for historical reasons, this option is
+    disabled by default in the ``settings.py`` file generated by the
+    :command:`startproject` command.
+
+By default, when loading spiders, Scrapy only loads
+:class:`~scrapy.spiders.Spider` subclasses that have a non-empty
+:attr:`~scrapy.Spider.name` unless they are decorated with
+:func:`~scrapy.spiders.ignore_spider`.
+
+If :setting:`SPIDER_LOADER_REQUIRE_NAME` is ``False``, Scrapy loads all
+:class:`~scrapy.spiders.Spider` subclasses unless they are decorated with
+:func:`~scrapy.spiders.ignore_spider`. If they do not have a non-empty
+:attr:`~scrapy.Spider.name`, their fully-qualified class name is used
+as a name.
+
+.. note:: This is a :ref:`pre-crawler setting <pre-crawler-settings>`.
+
 .. setting:: SPIDER_LOADER_WARN_ONLY
 
 SPIDER_LOADER_WARN_ONLY
diff --git a/docs/topics/spiders.rst b/docs/topics/spiders.rst
index 95c80d5dc..dfee5ec5d 100644
--- a/docs/topics/spiders.rst
+++ b/docs/topics/spiders.rst
@@ -40,11 +40,16 @@ scrapy.Spider
 
    .. attribute:: name
 
-       A string which defines the name for this spider. The spider name is how
-       the spider is located (and instantiated) by Scrapy, so it must be
-       unique. However, nothing prevents you from instantiating more than one
-       instance of the same spider. This is the most important spider attribute
-       and it's required.
+       A string which defines the name for this spider.
+
+       If :setting:`SPIDER_LOADER_REQUIRE_NAME` is ``True`` and you use the
+       default Scrapy spider loader (see :setting:`SPIDER_LOADER_CLASS`), a
+       non-empty name is required for the spider to be discoverable by the
+       Scrapy commands :command:`crawl` and :command:`list`.
+
+       The spider name must be unique to one spider class. If two or more
+       spiders have the same name, Scrapy commands :command:`crawl` and
+       :command:`runspider` will only be able to run one of the spiders.
 
        If the spider scrapes a single domain, a common practice is to name the
        spider after the domain, with or without the `TLD`_. So, for example, a
@@ -1002,3 +1007,29 @@ Combine SitemapSpider with other sources of urls:
 .. _robots.txt: https://www.robotstxt.org/
 .. _TLD: https://en.wikipedia.org/wiki/Top-level_domain
 .. _Scrapyd documentation: https://scrapyd.readthedocs.io/en/latest/
+
+
+Base spiders
+============
+
+Base spiders are :class:`~scrapy.spiders.Spider` subclasses that are not meant
+to be run by Scrapy. They are only meant to be subclassed to create regular
+spiders or other base spiders. They are one way to share code between two or
+more spiders.
+
+Use the :func:`~scrapy.spiders.ignore_spider` decorator to mark any base spider
+class:
+
+.. autodecorator:: scrapy.spiders.ignore_spider
+
+For example::
+
+    from scrapy.spiders import ignore_spider, Spider
+
+    @ignore_spider
+    class MyBaseSpider(Spider):
+        pass
+
+If :setting:`SPIDER_LOADER_REQUIRE_NAME` is ``True`` (default), any
+:class:`~scrapy.spiders.Spider` subclass without a ``name`` class attribute is
+also ignored.
diff --git a/scrapy/cmdline.py b/scrapy/cmdline.py
index e6d5ff96a..a8c33d74f 100644
--- a/scrapy/cmdline.py
+++ b/scrapy/cmdline.py
@@ -38,8 +38,6 @@ class ScrapyArgumentParser(argparse.ArgumentParser):
 
 
 def _iter_command_classes(module_name: str) -> Iterable[type[ScrapyCommand]]:
-    # TODO: add `name` attribute to commands and merge this function with
-    # scrapy.utils.spider.iter_spider_classes
     for module in walk_modules_iter(module_name):
         for obj in vars(module).values():
             if (
diff --git a/scrapy/commands/check.py b/scrapy/commands/check.py
index 2113c19d2..8d7eca877 100644
--- a/scrapy/commands/check.py
+++ b/scrapy/commands/check.py
@@ -98,7 +98,7 @@ class Command(ScrapyCommand):
                 tested_methods = conman.tested_methods_from_spidercls(spidercls)
                 if opts.list:
                     for method in tested_methods:
-                        contract_reqs[spidercls.name].append(method)
+                        contract_reqs[spidername].append(method)
                 elif tested_methods:
                     self.crawler_process.crawl(spidercls)
 
diff --git a/scrapy/commands/runspider.py b/scrapy/commands/runspider.py
index 9cdb393ab..d24b85918 100644
--- a/scrapy/commands/runspider.py
+++ b/scrapy/commands/runspider.py
@@ -53,10 +53,14 @@ class Command(BaseRunSpiderCommand):
             module = _import_file(filename)
         except (ImportError, ValueError) as e:
             raise UsageError(f"Unable to load {str(filename)!r}: {e}\n") from e
-        spclasses = list(iter_spider_classes(module))
+        # The spider is looked up by file name, so it does not need a name of
+        # its own. Named spiders still win over nameless ones, which in a file
+        # with both are usually base spiders.
+        spclasses = list(iter_spider_classes(module, require_name=False))
         if not spclasses:
             raise UsageError(f"No spider found in file: {filename}\n")
-        spidercls = spclasses.pop()
+        named = [spcls for spcls in spclasses if getattr(spcls, "name", None)]
+        spidercls = (named or spclasses).pop()
 
         assert self.crawler_process
         self.crawler_process.crawl(spidercls, **opts.spargs)
diff --git a/scrapy/settings/default_settings.py b/scrapy/settings/default_settings.py
index b97844103..c1a7280ad 100644
--- a/scrapy/settings/default_settings.py
+++ b/scrapy/settings/default_settings.py
@@ -550,6 +550,7 @@ SPIDER_CONTRACTS_BASE = {
 }
 
 SPIDER_LOADER_CLASS = "scrapy.spiderloader.SpiderLoader"
+SPIDER_LOADER_REQUIRE_NAME = True
 SPIDER_LOADER_WARN_ONLY = False
 
 SPIDER_MIDDLEWARES = {}
diff --git a/scrapy/spiderloader.py b/scrapy/spiderloader.py
index 244b7338f..199f2d859 100644
--- a/scrapy/spiderloader.py
+++ b/scrapy/spiderloader.py
@@ -55,6 +55,7 @@ class SpiderLoader:
     """
 
     def __init__(self, settings: BaseSettings):
+        self.require_name: bool = settings.getbool("SPIDER_LOADER_REQUIRE_NAME")
         self.spider_modules: list[str] = settings.getlist("SPIDER_MODULES")
         self.warn_only: bool = settings.getbool("SPIDER_LOADER_WARN_ONLY")
         self._spiders: dict[str, type[Spider]] = {}
@@ -82,9 +83,10 @@ class SpiderLoader:
             )
 
     def _load_spiders(self, module: ModuleType) -> None:
-        for spcls in iter_spider_classes(module):
-            self._found[spcls.name].append((module.__name__, spcls.__name__))
-            self._spiders[spcls.name] = spcls
+        for spcls in iter_spider_classes(module, require_name=self.require_name):
+            name = spcls._default_name()
+            self._found[name].append((module.__name__, spcls.__name__))
+            self._spiders[name] = spcls
 
     def _load_all_spiders(self) -> None:
         for name in self.spider_modules:
diff --git a/scrapy/spiders/__init__.py b/scrapy/spiders/__init__.py
index 6244e3264..cc5f9e487 100644
--- a/scrapy/spiders/__init__.py
+++ b/scrapy/spiders/__init__.py
@@ -8,11 +8,12 @@ from __future__ import annotations
 
 import logging
 import warnings
-from typing import TYPE_CHECKING, Any, cast
+from typing import TYPE_CHECKING, Any, TypeVar, cast
 
 from scrapy import signals
 from scrapy.exceptions import ScrapyDeprecationWarning
 from scrapy.http import Request, Response
+from scrapy.utils.python import global_object_name
 from scrapy.utils.trackref import object_ref
 from scrapy.utils.url import url_is_from_spider
 
@@ -30,6 +31,21 @@ if TYPE_CHECKING:
     from scrapy.utils.log import SpiderLoggerAdapter
 
 
+_SpiderT = TypeVar("_SpiderT", bound="type[Spider]")
+
+
+def ignore_spider(cls: _SpiderT) -> _SpiderT:
+    """Mark a :class:`~scrapy.spiders.Spider` subclass to be ignored.
+
+    Marked spider classes are not available to the :command:`crawl`,
+    :command:`list` and :command:`runspider` commands. Only the decorated
+    class is marked; its subclasses are unaffected.
+    """
+    cls._ignore_spider = True
+    return cls
+
+
+@ignore_spider
 class Spider(object_ref):
     """Base class that any spider must subclass.
 
@@ -40,6 +56,7 @@ class Spider(object_ref):
 
     name: str
     custom_settings: dict[str, Any] | None = None
+    _ignore_spider: bool
 
     #: Start URLs. See :meth:`start`.
     start_urls: list[str]
@@ -48,11 +65,23 @@ class Spider(object_ref):
         if name is not None:
             self.name: str = name
         elif not getattr(self, "name", None):
-            raise ValueError(f"{type(self).__name__} must have a name")
+            self.name = type(self)._default_name()
         self.__dict__.update(kwargs)
         if not hasattr(self, "start_urls"):
             self.start_urls: list[str] = []
 
+    @classmethod
+    def _default_name(cls) -> str:
+        """Return the name under which spider loaders and commands know this
+        spider class, which falls back to its import path."""
+        return getattr(cls, "name", None) or global_object_name(cls)
+
+    @classmethod
+    def _is_ignored(cls) -> bool:
+        # The mark set by ignore_spider() is read from the class __dict__ so
+        # that subclasses do not inherit it.
+        return "_ignore_spider" in cls.__dict__
+
     @property
     def logger(self) -> SpiderLoggerAdapter:
         # circular import
diff --git a/scrapy/spiders/crawl.py b/scrapy/spiders/crawl.py
index 373c0b8b5..181dfda08 100644
--- a/scrapy/spiders/crawl.py
+++ b/scrapy/spiders/crawl.py
@@ -16,7 +16,7 @@ from scrapy.exceptions import ScrapyDeprecationWarning
 from scrapy.http import HtmlResponse, Request, Response
 from scrapy.link import Link
 from scrapy.linkextractors import LinkExtractor
-from scrapy.spiders import Spider
+from scrapy.spiders import Spider, ignore_spider
 from scrapy.utils.asyncgen import collect_asyncgen
 from scrapy.utils.deprecate import method_is_overridden
 from scrapy.utils.python import global_object_name
@@ -95,6 +95,7 @@ class Rule:
         )
 
 
+@ignore_spider
 class CrawlSpider(Spider):
     rules: Sequence[Rule] = ()
     _rules: list[Rule]
diff --git a/scrapy/spiders/feed.py b/scrapy/spiders/feed.py
index 1e7ac9c34..b2f12c990 100644
--- a/scrapy/spiders/feed.py
+++ b/scrapy/spiders/feed.py
@@ -12,7 +12,7 @@ from typing import TYPE_CHECKING, Any
 from scrapy.exceptions import NotSupported
 from scrapy.http import Response, TextResponse
 from scrapy.selector import Selector
-from scrapy.spiders import Spider
+from scrapy.spiders import Spider, ignore_spider
 from scrapy.utils.iterators import csviter, xmliter_lxml
 from scrapy.utils.spider import iterate_spider_output
 
@@ -20,6 +20,7 @@ if TYPE_CHECKING:
     from collections.abc import Iterable, Sequence
 
 
+@ignore_spider
 class XMLFeedSpider(Spider):
     """
     This class intends to be the base class for spiders that scrape
@@ -107,6 +108,7 @@ class XMLFeedSpider(Spider):
             selector.register_namespace(prefix, uri)
 
 
+@ignore_spider
 class CSVFeedSpider(Spider):
     """Spider for parsing CSV feeds.
     It receives a CSV file in a response; iterates through each of its rows,
diff --git a/scrapy/spiders/sitemap.py b/scrapy/spiders/sitemap.py
index 2a80b8d24..cfbe8d2e3 100644
--- a/scrapy/spiders/sitemap.py
+++ b/scrapy/spiders/sitemap.py
@@ -8,7 +8,7 @@ from collections.abc import AsyncIterator, Iterable, Sequence  # noqa: TC003
 from typing import TYPE_CHECKING, Any, cast
 
 from scrapy.http import Request, Response, XmlResponse
-from scrapy.spiders import Spider
+from scrapy.spiders import Spider, ignore_spider
 from scrapy.utils._compression import _DecompressionMaxSizeExceeded
 from scrapy.utils.gz import gunzip, gzip_magic_number
 from scrapy.utils.sitemap import Sitemap, sitemap_urls_from_robots
@@ -23,6 +23,7 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
+@ignore_spider
 class SitemapSpider(Spider):
     sitemap_urls: Sequence[str] = ()
     sitemap_rules: Sequence[tuple[re.Pattern[str] | str, str | CallbackT]] = [
diff --git a/scrapy/templates/project/module/settings.py.tmpl b/scrapy/templates/project/module/settings.py.tmpl
index 0432a7231..2735c5477 100644
--- a/scrapy/templates/project/module/settings.py.tmpl
+++ b/scrapy/templates/project/module/settings.py.tmpl
@@ -83,5 +83,8 @@ DOWNLOAD_DELAY = 1
 #HTTPCACHE_IGNORE_HTTP_CODES = []
 #HTTPCACHE_STORAGE = "scrapy.extensions.httpcache.FilesystemCacheStorage"
 
+# Allow listing and running spiders that do not have a name
+SPIDER_LOADER_REQUIRE_NAME = False
+
 # Set settings whose default value is deprecated to a future-proof value
 FEED_EXPORT_ENCODING = "utf-8"
diff --git a/scrapy/utils/spider.py b/scrapy/utils/spider.py
index 9f43df1ce..42b43b7d0 100644
--- a/scrapy/utils/spider.py
+++ b/scrapy/utils/spider.py
@@ -47,18 +47,27 @@ def iterate_spider_output(
     return arg_to_iter(d)
 
 
-def iter_spider_classes(module: ModuleType) -> Iterable[type[Spider]]:
-    """Return an iterator over all spider classes defined in the given module
-    that can be instantiated (i.e. which have name)
+def iter_spider_classes(
+    module: ModuleType,
+    *,
+    require_name: bool = True,
+) -> Iterable[type[Spider]]:
+    """Return an iterator over all :class:`~scrapy.spiders.Spider` subclasses
+    defined in the given module, excluding those marked with
+    :func:`scrapy.spiders.ignore_spider`.
+
+    If `require_name` is ``True`` (default), any
+    :class:`~scrapy.spiders.Spider` subclass without a non-empty
+    :attr:`~scrapy.Spider.name` is also excluded.
     """
     for obj in vars(module).values():
-        if (
-            inspect.isclass(obj)
-            and issubclass(obj, Spider)
-            and obj.__module__ == module.__name__
-            and getattr(obj, "name", None)
-        ):
-            yield obj
+        if not inspect.isclass(obj) or not issubclass(obj, Spider):
+            continue
+        if obj.__module__ != module.__name__ or obj._is_ignored():
+            continue
+        if require_name and not getattr(obj, "name", None):
+            continue
+        yield obj
 
 
 @overload
diff --git a/scrapy/utils/url.py b/scrapy/utils/url.py
index f67853ece..22956d442 100644
--- a/scrapy/utils/url.py
+++ b/scrapy/utils/url.py
@@ -28,7 +28,10 @@ def url_is_from_any_domain(url: UrlT, domains: Iterable[str]) -> bool:
 
 
 def _spider_domains(spider: type[Spider]) -> Iterable[str]:
-    yield spider.name
+    # Spiders that get their name from their import path have no class-level
+    # name, and an import path is never a domain anyway.
+    if name := getattr(spider, "name", None):
+        yield name
     if allowed_domains := getattr(spider, "allowed_domains", None):
         yield from allowed_domains
 
diff --git a/tests/test_command_check.py b/tests/test_command_check.py
index 240f44584..a8ccf92c1 100644
--- a/tests/test_command_check.py
+++ b/tests/test_command_check.py
@@ -122,6 +122,25 @@ class CheckSpider(scrapy.Spider):
         """
         self._test_contract(proj_path, contracts, parse_def)
 
+    def test_check_list_nameless_spider(self, proj_path: Path) -> None:
+        spider = proj_path / self.project_name / "spiders" / "namelessspider.py"
+        spider.write_text(
+            '''
+import scrapy
+
+class NamelessSpider(scrapy.Spider):
+    def parse(self, response):
+        """
+        @url data:,
+        """
+''',
+            encoding="utf-8",
+        )
+        name = f"{self.project_name}.spiders.namelessspider.NamelessSpider"
+        ret, out, err = proc("check", "-l", name, cwd=proj_path)
+        assert ret == 0, err
+        assert out == f"{name}\n  * parse\n"
+
     def test_SCRAPY_CHECK_set(self, proj_path: Path) -> None:
         parse_def = """
         import os
diff --git a/tests/test_command_crawl.py b/tests/test_command_crawl.py
index 5306e3bf8..94b1cc21a 100644
--- a/tests/test_command_crawl.py
+++ b/tests/test_command_crawl.py
@@ -35,6 +35,24 @@ class TestCrawlCommand(TestProjectBase):
             "running 'scrapy crawl' with more than one spider is not supported" in err
         )
 
+    def test_nameless_spider(self, proj_path: Path) -> None:
+        spider_code = """
+import scrapy
+
+class MySpider(scrapy.Spider):
+    async def start(self):
+        self.logger.debug('It works!')
+        return
+        yield
+"""
+        (proj_path / self.project_name / "spiders" / "myspider.py").write_text(
+            spider_code, encoding="utf-8"
+        )
+        name = f"{self.project_name}.spiders.myspider.MySpider"
+        _, _, log = proc("crawl", name, cwd=proj_path)
+        assert f"[{name}] DEBUG: It works!" in log
+        assert "Spider closed (finished)" in log
+
     def test_no_output(self, proj_path: Path) -> None:
         spider_code = """
 import scrapy
diff --git a/tests/test_command_runspider.py b/tests/test_command_runspider.py
index 11036eaeb..6e8213b67 100644
--- a/tests/test_command_runspider.py
+++ b/tests/test_command_runspider.py
@@ -132,6 +132,39 @@ class MySpider(scrapy.Spider):
         assert ("[scrapy]" in log1) is value
         assert ("[scrapy.core.engine]" in log1) is not value
 
+    def test_runspider_nameless_spider(self, tmp_path: Path) -> None:
+        nameless_spider = """
+import scrapy
+
+class MySpider(scrapy.Spider):
+    async def start(self):
+        self.logger.debug("It Works!")
+        return
+        yield
+"""
+        log = self.get_log(tmp_path, nameless_spider)
+        assert "[myspider.MySpider] DEBUG: It Works!" in log
+        assert "INFO: Spider closed (finished)" in log
+
+    def test_runspider_prefers_named_spider(self, tmp_path: Path) -> None:
+        """A base spider defined after the spider itself does not shadow it."""
+        base_last_spider = """
+import scrapy
+
+class MySpider(scrapy.Spider):
+    name = 'myspider'
+
+    async def start(self):
+        self.logger.debug("It Works!")
+        return
+        yield
+
+class MyBaseSpider(scrapy.Spider):
+    pass
+"""
+        log = self.get_log(tmp_path, base_last_spider)
+        assert "[myspider] DEBUG: It Works!" in log
+
     def test_runspider_no_spider_found(self, tmp_path: Path) -> None:
         log = self.get_log(tmp_path, "from scrapy.spiders import Spider\n")
         assert "No spider found in file" in log
diff --git a/tests/test_commands.py b/tests/test_commands.py
index f20ecc153..943a9c43b 100644
--- a/tests/test_commands.py
+++ b/tests/test_commands.py
@@ -432,6 +432,31 @@ class TestMiscCommands(TestProjectBase):
         subdir.mkdir(exist_ok=True)
         assert call("list", cwd=subdir) == 0
 
+    @pytest.mark.parametrize("require_name", [False, True])
+    def test_list_nameless(self, proj_path: Path, require_name: bool) -> None:
+        (proj_path / self.project_name / "spiders" / "nameless.py").write_text(
+            "from scrapy import Spider\n"
+            "\n"
+            "\n"
+            "class NamelessSpider(Spider):\n"
+            "    pass\n"
+            "\n"
+            "\n"
+            "class NamedSpider(Spider):\n"
+            '    name = "named"\n',
+            encoding="utf-8",
+        )
+        returncode, out, err = proc(
+            "list",
+            "-s",
+            f"SPIDER_LOADER_REQUIRE_NAME={require_name}",
+            cwd=proj_path,
+        )
+        assert returncode == 0, err
+        nameless = f"{self.project_name}.spiders.nameless.NamelessSpider"
+        expected = ["named"] if require_name else ["named", nameless]
+        assert out.split() == expected
+
 
 class TestCommandListing(TestProjectBase):
     """Tests for the command list that ``scrapy`` prints when called without a
diff --git a/tests/test_spiderloader/__init__.py b/tests/test_spiderloader/__init__.py
index 81840f7e0..951d4fa76 100644
--- a/tests/test_spiderloader/__init__.py
+++ b/tests/test_spiderloader/__init__.py
@@ -1,6 +1,7 @@
 import contextlib
 import shutil
 import sys
+import warnings
 from pathlib import Path
 from unittest import mock
 
@@ -13,6 +14,7 @@ from scrapy.crawler import CrawlerRunner
 from scrapy.http import Request
 from scrapy.settings import Settings
 from scrapy.spiderloader import DummySpiderLoader, SpiderLoader, get_spider_loader
+from tests.test_spiderloader.nameless_spiders.nameless1 import NamelessSpider
 
 module_dir = Path(__file__).resolve().parent
 
@@ -165,6 +167,69 @@ class TestSpiderLoader:
         assert not spiders
 
 
+class TestNamelessSpiderLoader:
+    module = "tests.test_spiderloader.nameless_spiders"
+    nameless1 = f"{module}.nameless1.NamelessSpider"
+    nameless2 = f"{module}.nameless2.NamelessSpider"
+
+    @pytest.fixture
+    def spider_loader(self):
+        settings = Settings(
+            {
+                "SPIDER_MODULES": [self.module],
+                "SPIDER_LOADER_REQUIRE_NAME": False,
+            }
+        )
+        return SpiderLoader.from_settings(settings)
+
+    def test_list(self, spider_loader):
+        assert set(spider_loader.list()) == {
+            "subclass",
+            self.nameless1,
+            self.nameless2,
+        }
+
+    def test_list_require_name(self):
+        settings = Settings({"SPIDER_MODULES": [self.module]})
+        spider_loader = SpiderLoader.from_settings(settings)
+        assert set(spider_loader.list()) == {"subclass"}
+
+    def test_load(self, spider_loader):
+        assert spider_loader.load(self.nameless1) is NamelessSpider
+
+    def test_instance_name(self, spider_loader):
+        """Spiders are instantiated with the name that the loader knows them
+        by."""
+        for name in spider_loader.list():
+            assert spider_loader.load(name)().name == name
+
+    def test_find_by_request(self, spider_loader):
+        assert spider_loader.find_by_request(
+            Request("https://nameless.example.com")
+        ) == [self.nameless1]
+
+    def test_no_dupename_warning(self):
+        settings = Settings(
+            {
+                "SPIDER_MODULES": [self.module],
+                "SPIDER_LOADER_REQUIRE_NAME": False,
+            }
+        )
+        with warnings.catch_warnings():
+            warnings.simplefilter("error", UserWarning)
+            SpiderLoader.from_settings(settings)
+
+    def test_crawler_runner_loading(self, spider_loader):
+        runner = CrawlerRunner(
+            {
+                "SPIDER_MODULES": [self.module],
+                "SPIDER_LOADER_REQUIRE_NAME": False,
+            }
+        )
+        crawler = runner.create_crawler(self.nameless1)
+        assert crawler.spidercls is NamelessSpider
+
+
 class TestDuplicateSpiderNameLoader:
     def test_dupename_warning(self, spider_loader_env):
         settings, spiders_dir = spider_loader_env
diff --git a/tests/test_spiderloader/nameless_spiders/__init__.py b/tests/test_spiderloader/nameless_spiders/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/test_spiderloader/nameless_spiders/ignored.py b/tests/test_spiderloader/nameless_spiders/ignored.py
new file mode 100644
index 000000000..fd9113eae
--- /dev/null
+++ b/tests/test_spiderloader/nameless_spiders/ignored.py
@@ -0,0 +1,10 @@
+from scrapy.spiders import Spider, ignore_spider
+
+
+@ignore_spider
+class IgnoredSpider(Spider):
+    name = "ignored"
+
+
+class SubclassSpider(IgnoredSpider):
+    name = "subclass"
diff --git a/tests/test_spiderloader/nameless_spiders/nameless1.py b/tests/test_spiderloader/nameless_spiders/nameless1.py
new file mode 100644
index 000000000..dc910cdd4
--- /dev/null
+++ b/tests/test_spiderloader/nameless_spiders/nameless1.py
@@ -0,0 +1,5 @@
+from scrapy.spiders import Spider
+
+
+class NamelessSpider(Spider):
+    allowed_domains = ["nameless.example.com"]
diff --git a/tests/test_spiderloader/nameless_spiders/nameless2.py b/tests/test_spiderloader/nameless_spiders/nameless2.py
new file mode 100644
index 000000000..83c0364d8
--- /dev/null
+++ b/tests/test_spiderloader/nameless_spiders/nameless2.py
@@ -0,0 +1,7 @@
+from scrapy.spiders import Spider
+
+
+# Same class name as in the nameless1 module, to check that nameless spiders
+# are told apart by their full import path.
+class NamelessSpider(Spider):
+    pass
diff --git a/tests/test_utils_spider.py b/tests/test_utils_spider.py
index 71f0f76ad..e1eddf052 100644
--- a/tests/test_utils_spider.py
+++ b/tests/test_utils_spider.py
@@ -3,15 +3,46 @@ from __future__ import annotations
 from scrapy import Spider
 from scrapy.http import Request
 from scrapy.item import Item
+from scrapy.spiders import ignore_spider
 from scrapy.utils.spider import iter_spider_classes, iterate_spider_output
 
 
-class MySpider1(Spider):
-    name = "myspider1"
+class SpiderA(Spider):
+    pass
 
 
-class MySpider2(Spider):
-    name = "myspider2"
+@ignore_spider
+class SpiderB(Spider):
+    pass
+
+
+@ignore_spider
+class SpiderC(Spider):
+    name = "c"
+
+
+class SpiderA1(SpiderA):
+    name = "a1"
+
+
+class SpiderA2(SpiderA):
+    pass
+
+
+class SpiderB1(SpiderB):
+    name = "b1"
+
+
+class SpiderB2(SpiderB):
+    pass
+
+
+class SpiderC1(SpiderC):
+    name = "c1"
+
+
+class SpiderC2(SpiderC):
+    pass
 
 
 def test_iterate_spider_output():
@@ -25,8 +56,23 @@ def test_iterate_spider_output():
     assert list(iterate_spider_output([r, i, o])) == [r, i, o]
 
 
-def test_iter_spider_classes():
+def test_iter_spider_classes_require_name():
     import tests.test_utils_spider  # noqa: PLW0406,PLC0415
 
-    it = iter_spider_classes(tests.test_utils_spider)
-    assert set(it) == {MySpider1, MySpider2}
+    it = iter_spider_classes(tests.test_utils_spider, require_name=True)
+    assert set(it) == {SpiderA1, SpiderB1, SpiderC1, SpiderC2}
+
+
+def test_iter_spider_classes_dont_require_name():
+    import tests.test_utils_spider  # noqa: PLW0406,PLC0415
+
+    it = iter_spider_classes(tests.test_utils_spider, require_name=False)
+    assert set(it) == {
+        SpiderA,
+        SpiderA1,
+        SpiderA2,
+        SpiderB1,
+        SpiderB2,
+        SpiderC1,
+        SpiderC2,
+    }
diff --git a/tests/utils/bases/spider.py b/tests/utils/bases/spider.py
index 799c1820d..db3b0033e 100644
--- a/tests/utils/bases/spider.py
+++ b/tests/utils/bases/spider.py
@@ -11,6 +11,7 @@ from scrapy import signals
 from scrapy.crawler import Crawler
 from scrapy.exceptions import ScrapyDeprecationWarning
 from scrapy.settings import Settings
+from scrapy.utils.python import global_object_name
 from scrapy.utils.test import get_crawler, get_reactor_settings
 from tests.utils.decorators import inline_callbacks_test
 
@@ -35,12 +36,20 @@ class TestSpiderBase(ABC):
         assert spider.foo == "bar"
 
     def test_spider_without_name(self):
-        """``__init__`` raises when the name is not provided."""
-        msg = "must have a name"
-        with pytest.raises(ValueError, match=msg):
-            self.spider_class()
-        with pytest.raises(ValueError, match=msg):
-            self.spider_class(somearg="foo")
+        """Spiders with no name get their import path as name."""
+        assert not hasattr(self.spider_class, "name")
+        spider = self.spider_class()
+        assert spider.name == global_object_name(self.spider_class)
+
+    def test_ignored(self):
+        """Base spiders shipped by Scrapy are ignored, their subclasses are
+        not."""
+
+        class Subclass(self.spider_class):
+            pass
+
+        assert self.spider_class._is_ignored()
+        assert not Subclass._is_ignored()
 
     def test_from_crawler_crawler_and_settings_population(self):
         crawler = get_crawler()
diff --git a/tox.ini b/tox.ini
index 7ea1c57d7..3d150ac86 100644
--- a/tox.ini
+++ b/tox.ini
@@ -113,7 +113,8 @@ commands =
     pre-commit run {posargs:--all-files}
 
 [testenv:pylint]
-# Some checks are Python-version-dependent, so pin the version used in CI.
+# Version-dependent code and pylint suppressions require a fixed interpreter.
+# Keep in sync with the pylint job in .github/workflows/checks.yml.
 basepython = python3.14
 deps =
     {[testenv:extra-deps]deps}