diff --git a/scrapy/commands/crawl.py b/scrapy/commands/crawl.py
index 00d63dbe1..53d2137dc 100644
--- a/scrapy/commands/crawl.py
+++ b/scrapy/commands/crawl.py
@@ -19,6 +19,8 @@ class Command(ScrapyCommand):
                           help="set spider argument (may be repeated)")
         parser.add_option("-o", "--output", metavar="FILE",
                           help="dump scraped items into FILE (use - for stdout)")
+        parser.add_option("-t", "--output-format", metavar="FORMAT", default="jsonlines",
+                          help="format to use for dumping items with -o (default: %default)")
 
     def process_options(self, args, opts):
         ScrapyCommand.process_options(self, args, opts)
@@ -32,7 +34,8 @@ class Command(ScrapyCommand):
             else:
                 self.settings.overrides['FEED_URI'] = opts.output
             valid_output_formats = self.settings['FEED_EXPORTERS'].keys() + self.settings['FEED_EXPORTERS_BASE'].keys()
-            opts.output_format = os.path.splitext(opts.output)[1].replace(".", "")
+            if not opts.output_format:
+                opts.output_format = os.path.splitext(opts.output)[1].replace(".", "")
             if opts.output_format not in valid_output_formats:
                 raise UsageError('Invalid/unrecognized output format: %s, Expected %s' % (opts.output_format, valid_output_formats))
             self.settings.overrides['FEED_FORMAT'] = opts.output_format
diff --git a/scrapy/commands/runspider.py b/scrapy/commands/runspider.py
index 1bbcef880..414f4c43f 100644
--- a/scrapy/commands/runspider.py
+++ b/scrapy/commands/runspider.py
@@ -41,6 +41,8 @@ class Command(ScrapyCommand):
                           help="set spider argument (may be repeated)")
         parser.add_option("-o", "--output", metavar="FILE",
                           help="dump scraped items into FILE (use - for stdout)")
+        parser.add_option("-t", "--output-format", metavar="FORMAT", default="jsonlines",
+                          help="format to use for dumping items with -o (default: %default)")
 
     def process_options(self, args, opts):
         ScrapyCommand.process_options(self, args, opts)
@@ -54,7 +56,8 @@ class Command(ScrapyCommand):
             else:
                 self.settings.overrides['FEED_URI'] = opts.output
             valid_output_formats = self.settings['FEED_EXPORTERS'].keys() + self.settings['FEED_EXPORTERS_BASE'].keys()
-            opts.output_format = os.path.splitext(opts.output)[1].replace(".", "")
+            if not opts.output_format:
+                opts.output_format = os.path.splitext(opts.output)[1].replace(".", "")
             if opts.output_format not in valid_output_formats:
                 raise UsageError('Invalid/unrecognized output format: %s, Expected %s' % (opts.output_format, valid_output_formats))
             self.settings.overrides['FEED_FORMAT'] = opts.output_format