diff --git a/docs/topics/link-extractors.rst b/docs/topics/link-extractors.rst
index 4636ddb18..75bdb4142 100644
--- a/docs/topics/link-extractors.rst
+++ b/docs/topics/link-extractors.rst
@@ -51,7 +51,7 @@ LxmlLinkExtractor
    :synopsis: lxml's HTMLParser-based link extractors
 
 
-.. class:: LxmlLinkExtractor(allow=(), deny=(), allow_domains=(), deny_domains=(), deny_extensions=None, restrict_xpaths=(), restrict_css=(), tags=('a', 'area'), attrs=('href',), canonicalize=True, unique=True, process_value=None)
+.. class:: LxmlLinkExtractor(allow=(), deny=(), allow_domains=(), deny_domains=(), deny_extensions=None, restrict_xpaths=(), restrict_css=(), tags=('a', 'area'), attrs=('href',), canonicalize=True, unique=True, process_value=None, strip=True)
 
     LxmlLinkExtractor is the recommended link extractor with handy filtering
     options. It is implemented using lxml's robust HTMLParser.
@@ -132,4 +132,13 @@ LxmlLinkExtractor
 
     :type process_value: callable
 
+    :param strip: whether to strip whitespaces from extracted attributes.
+        According to HTML5 standard, leading and trailing whitespaces
+        must be stripped from ``href`` attributes of ``<a>``, ``<area>``
+        and many other elements, ``src`` attribute of ``<img>``, ``<iframe>``
+        elements, etc., so LinkExtractor strips space chars by default.
+        Set ``strip=False`` to turn it off (e.g. if you're extracting urls
+        from elements or attributes which allow leading/trailing whitespaces).
+    :type strip: boolean
+
 .. _scrapy.linkextractors: https://github.com/scrapy/scrapy/blob/master/scrapy/linkextractors/__init__.py
diff --git a/requirements-py3.txt b/requirements-py3.txt
index 08ccf1958..cc0a7f644 100644
--- a/requirements-py3.txt
+++ b/requirements-py3.txt
@@ -3,5 +3,5 @@ lxml>=3.2.4
 pyOpenSSL>=0.13.1
 cssselect>=0.9
 queuelib>=1.1.1
-w3lib>=1.14.2
+w3lib>=1.17.0
 service_identity
diff --git a/requirements.txt b/requirements.txt
index f92603d3d..392f83dd6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ Twisted>=13.1.0
 lxml
 pyOpenSSL
 cssselect>=0.9
-w3lib>=1.15.0
+w3lib>=1.17.0
 queuelib
 six>=1.5.2
 PyDispatcher>=2.0.5
diff --git a/scrapy/linkextractors/htmlparser.py b/scrapy/linkextractors/htmlparser.py
index 9867e1179..27978a8a1 100644
--- a/scrapy/linkextractors/htmlparser.py
+++ b/scrapy/linkextractors/htmlparser.py
@@ -1,13 +1,13 @@
 """
 HTMLParser-based link extractor
 """
-
 import warnings
 import six
 from six.moves.html_parser import HTMLParser
 from six.moves.urllib.parse import urljoin
 
 from w3lib.url import safe_url_string
+from w3lib.html import strip_html5_whitespace
 
 from scrapy.link import Link
 from scrapy.utils.python import unique as unique_list
@@ -16,7 +16,8 @@ from scrapy.exceptions import ScrapyDeprecationWarning
 
 class HtmlParserLinkExtractor(HTMLParser):
 
-    def __init__(self, tag="a", attr="href", process=None, unique=False):
+    def __init__(self, tag="a", attr="href", process=None, unique=False,
+                 strip=True):
         HTMLParser.__init__(self)
 
         warnings.warn(
@@ -29,6 +30,7 @@ class HtmlParserLinkExtractor(HTMLParser):
         self.scan_attr = attr if callable(attr) else lambda a: a == attr
         self.process_attr = process if callable(process) else lambda v: v
         self.unique = unique
+        self.strip = strip
 
     def _extract_links(self, response_text, response_url, response_encoding):
         self.reset()
@@ -69,6 +71,8 @@ class HtmlParserLinkExtractor(HTMLParser):
         if self.scan_tag(tag):
             for attr, value in attrs:
                 if self.scan_attr(attr):
+                    if self.strip:
+                        value = strip_html5_whitespace(value)
                     url = self.process_attr(value)
                     link = Link(url=url)
                     self.links.append(link)
diff --git a/scrapy/linkextractors/lxmlhtml.py b/scrapy/linkextractors/lxmlhtml.py
index 71d57b392..c284f1905 100644
--- a/scrapy/linkextractors/lxmlhtml.py
+++ b/scrapy/linkextractors/lxmlhtml.py
@@ -2,15 +2,16 @@
 Link extractor based on lxml.html
 """
 import six
-from six.moves.urllib.parse import urlparse, urljoin
+from six.moves.urllib.parse import urljoin
 
 import lxml.etree as etree
+from w3lib.html import strip_html5_whitespace
 
 from scrapy.link import Link
 from scrapy.utils.misc import arg_to_iter, rel_has_nofollow
 from scrapy.utils.python import unique as unique_list, to_native_str
-from scrapy.linkextractors import FilteringLinkExtractor
 from scrapy.utils.response import get_base_url
+from scrapy.linkextractors import FilteringLinkExtractor
 
 
 # from lxml/src/lxml/html/__init__.py
@@ -27,11 +28,13 @@ def _nons(tag):
 
 
 class LxmlParserLinkExtractor(object):
-    def __init__(self, tag="a", attr="href", process=None, unique=False):
+    def __init__(self, tag="a", attr="href", process=None, unique=False,
+                 strip=True):
         self.scan_tag = tag if callable(tag) else lambda t: t == tag
         self.scan_attr = attr if callable(attr) else lambda a: a == attr
         self.process_attr = process if callable(process) else lambda v: v
         self.unique = unique
+        self.strip = strip
 
     def _iter_links(self, document):
         for el in document.iter(etree.Element):
@@ -49,9 +52,11 @@ class LxmlParserLinkExtractor(object):
         for el, attr, attr_val in self._iter_links(selector.root):
             # pseudo lxml.html.HtmlElement.make_links_absolute(base_url)
             try:
+                if self.strip:
+                    attr_val = strip_html5_whitespace(attr_val)
                 attr_val = urljoin(base_url, attr_val)
             except ValueError:
-                continue # skipping bogus links
+                continue  # skipping bogus links
             else:
                 url = self.process_attr(attr_val)
                 if url is None:
@@ -85,12 +90,13 @@ class LxmlLinkExtractor(FilteringLinkExtractor):
 
     def __init__(self, allow=(), deny=(), allow_domains=(), deny_domains=(), restrict_xpaths=(),
                  tags=('a', 'area'), attrs=('href',), canonicalize=True,
-                 unique=True, process_value=None, deny_extensions=None, restrict_css=()):
+                 unique=True, process_value=None, deny_extensions=None, restrict_css=(),
+                 strip=True):
         tags, attrs = set(arg_to_iter(tags)), set(arg_to_iter(attrs))
         tag_func = lambda x: x in tags
         attr_func = lambda x: x in attrs
         lx = LxmlParserLinkExtractor(tag=tag_func, attr=attr_func,
-            unique=unique, process=process_value)
+            unique=unique, process=process_value, strip=strip)
 
         super(LxmlLinkExtractor, self).__init__(lx, allow=allow, deny=deny,
             allow_domains=allow_domains, deny_domains=deny_domains,
diff --git a/scrapy/linkextractors/regex.py b/scrapy/linkextractors/regex.py
index 0fc7b079f..e689b4727 100644
--- a/scrapy/linkextractors/regex.py
+++ b/scrapy/linkextractors/regex.py
@@ -10,9 +10,10 @@ linkre = re.compile(
         "<a\s.*?href=(\"[.#]+?\"|\'[.#]+?\'|[^\s]+?)(>|\s.*?>)(.*?)<[/ ]?a>",
         re.DOTALL | re.IGNORECASE)
 
+
 def clean_link(link_text):
     """Remove leading and trailing whitespace and punctuation"""
-    return link_text.strip("\t\r\n '\"")
+    return link_text.strip("\t\r\n '\"\x0c")
 
 
 class RegexLinkExtractor(SgmlLinkExtractor):
diff --git a/scrapy/linkextractors/sgml.py b/scrapy/linkextractors/sgml.py
index c68dae4c8..11ff7a261 100644
--- a/scrapy/linkextractors/sgml.py
+++ b/scrapy/linkextractors/sgml.py
@@ -7,7 +7,8 @@ import warnings
 from sgmllib import SGMLParser
 
 from w3lib.url import safe_url_string
-from scrapy.selector import Selector
+from w3lib.html import strip_html5_whitespace
+
 from scrapy.link import Link
 from scrapy.linkextractors import FilteringLinkExtractor
 from scrapy.utils.misc import arg_to_iter, rel_has_nofollow
@@ -18,7 +19,8 @@ from scrapy.exceptions import ScrapyDeprecationWarning
 
 class BaseSgmlLinkExtractor(SGMLParser):
 
-    def __init__(self, tag="a", attr="href", unique=False, process_value=None):
+    def __init__(self, tag="a", attr="href", unique=False, process_value=None,
+                 strip=True):
         warnings.warn(
             "BaseSgmlLinkExtractor is deprecated and will be removed in future releases. "
             "Please use scrapy.linkextractors.LinkExtractor",
@@ -30,6 +32,7 @@ class BaseSgmlLinkExtractor(SGMLParser):
         self.process_value = (lambda v: v) if process_value is None else process_value
         self.current_link = None
         self.unique = unique
+        self.strip = strip
 
     def _extract_links(self, response_text, response_url, response_encoding, base_url=None):
         """ Do the real extraction work """
@@ -79,6 +82,8 @@ class BaseSgmlLinkExtractor(SGMLParser):
         if self.scan_tag(tag):
             for attr, value in attrs:
                 if self.scan_attr(attr):
+                    if self.strip and value is not None:
+                        value = strip_html5_whitespace(value)
                     url = self.process_value(value)
                     if url is not None:
                         link = Link(url=url, nofollow=rel_has_nofollow(dict(attrs).get('rel')))
@@ -103,7 +108,8 @@ class SgmlLinkExtractor(FilteringLinkExtractor):
 
     def __init__(self, allow=(), deny=(), allow_domains=(), deny_domains=(), restrict_xpaths=(),
                  tags=('a', 'area'), attrs=('href',), canonicalize=True, unique=True,
-                 process_value=None, deny_extensions=None, restrict_css=()):
+                 process_value=None, deny_extensions=None, restrict_css=(),
+                 strip=True):
 
         warnings.warn(
             "SgmlLinkExtractor is deprecated and will be removed in future releases. "
@@ -118,7 +124,7 @@ class SgmlLinkExtractor(FilteringLinkExtractor):
         with warnings.catch_warnings():
             warnings.simplefilter('ignore', ScrapyDeprecationWarning)
             lx = BaseSgmlLinkExtractor(tag=tag_func, attr=attr_func,
-                unique=unique, process_value=process_value)
+                unique=unique, process_value=process_value, strip=strip)
 
         super(SgmlLinkExtractor, self).__init__(lx, allow=allow, deny=deny,
             allow_domains=allow_domains, deny_domains=deny_domains,
diff --git a/setup.py b/setup.py
index a6e6f9615..086ab8142 100644
--- a/setup.py
+++ b/setup.py
@@ -43,7 +43,7 @@ setup(
     ],
     install_requires=[
         'Twisted>=13.1.0',
-        'w3lib>=1.15.0',
+        'w3lib>=1.17.0',
         'queuelib',
         'lxml',
         'pyOpenSSL',
diff --git a/tests/sample_data/link_extractor/sgml_linkextractor.html b/tests/sample_data/link_extractor/sgml_linkextractor.html
index 35aa457ee..fbb803f2d 100644
--- a/tests/sample_data/link_extractor/sgml_linkextractor.html
+++ b/tests/sample_data/link_extractor/sgml_linkextractor.html
@@ -13,6 +13,7 @@
 <a href='sample3.html'>sample 3 repetition</a>
 <a href='http://www.google.com/something'></a>
 <a href='http://example.com/innertag.html'><b>inner</b> tag</a>
+<a href=' page 4.html '>href with whitespaces</a>
 </div>
 </body>
 </html>
diff --git a/tests/test_linkextractors.py b/tests/test_linkextractors.py
index 129336d14..340c64f35 100644
--- a/tests/test_linkextractors.py
+++ b/tests/test_linkextractors.py
@@ -32,6 +32,7 @@ class Base:
                 Link(url='http://example.com/sample3.html', text=u'sample 3 text'),
                 Link(url='http://www.google.com/something', text=u''),
                 Link(url='http://example.com/innertag.html', text=u'inner tag'),
+                Link(url='http://example.com/page%204.html', text=u'href with whitespaces'),
             ])
 
         def test_extract_filter_allow(self):
@@ -281,6 +282,7 @@ class Base:
                 Link(url='http://example.com/sample3.html', text=u'sample 3 text'),
                 Link(url='http://www.google.com/something', text=u''),
                 Link(url='http://example.com/innertag.html', text=u'inner tag'),
+                Link(url='http://example.com/page%204.html', text=u'href with whitespaces'),
             ])
 
             lx = self.extractor_cls(attrs=("href","src"), tags=("a","area","img"), deny_extensions=())
@@ -291,6 +293,7 @@ class Base:
                 Link(url='http://example.com/sample3.html', text=u'sample 3 text'),
                 Link(url='http://www.google.com/something', text=u''),
                 Link(url='http://example.com/innertag.html', text=u'inner tag'),
+                Link(url='http://example.com/page%204.html', text=u'href with whitespaces'),
             ])
 
             lx = self.extractor_cls(attrs=None)
diff --git a/tests/test_linkextractors_deprecated.py b/tests/test_linkextractors_deprecated.py
index 36dfe174f..fef227aa1 100644
--- a/tests/test_linkextractors_deprecated.py
+++ b/tests/test_linkextractors_deprecated.py
@@ -117,12 +117,14 @@ class HtmlParserLinkExtractorTestCase(unittest.TestCase):
     def test_extraction(self):
         # Default arguments
         lx = HtmlParserLinkExtractor()
-        self.assertEqual(lx.extract_links(self.response),
-                         [Link(url='http://example.com/sample2.html', text=u'sample 2'),
-                          Link(url='http://example.com/sample3.html', text=u'sample 3 text'),
-                          Link(url='http://example.com/sample3.html', text=u'sample 3 repetition'),
-                          Link(url='http://www.google.com/something', text=u''),
-                          Link(url='http://example.com/innertag.html', text=u'inner tag'),])
+        self.assertEqual(lx.extract_links(self.response), [
+            Link(url='http://example.com/sample2.html', text=u'sample 2'),
+            Link(url='http://example.com/sample3.html', text=u'sample 3 text'),
+            Link(url='http://example.com/sample3.html', text=u'sample 3 repetition'),
+            Link(url='http://www.google.com/something', text=u''),
+            Link(url='http://example.com/innertag.html', text=u'inner tag'),
+            Link(url='http://example.com/page%204.html', text=u'href with whitespaces'),
+        ])
 
     def test_link_wrong_href(self):
         html = """
@@ -220,3 +222,9 @@ class RegexLinkExtractorTestCase(unittest.TestCase):
         self.assertEqual([link for link in lx.extract_links(response)], [
             Link(url='http://b.com/test.html', text=u'', nofollow=False),
         ])
+
+    @unittest.expectedFailure
+    def test_extraction(self):
+        # RegexLinkExtractor doesn't parse URLs with leading/trailing
+        # whitespaces correctly.
+        super(RegexLinkExtractorTestCase, self).test_extraction()