diff -r 8ed6a627a834 Lib/test/test_textwrap.py
--- a/Lib/test/test_textwrap.py	Tue Oct 11 04:06:47 2011 +0200
+++ b/Lib/test/test_textwrap.py	Tue Oct 11 14:57:01 2011 +0200
@@ -91,6 +91,14 @@
         result = wrapper.fill(text)
         self.check(result, '\n'.join(expect))
 
+        text = "Test\tdefault\t\ttabsize."
+        expect = ["Test    default         tabsize."]
+        self.check_wrap(text, 80, expect)
+
+        text = "Test\tcustom\t\ttabsize."
+        expect = ["Test    custom      tabsize."]
+        self.check_wrap(text, 80, expect, tabsize=4)
+
     def test_fix_sentence_endings(self):
         wrapper = TextWrapper(60, fix_sentence_endings=True)
 
diff -r 8ed6a627a834 Lib/textwrap.py
--- a/Lib/textwrap.py	Tue Oct 11 04:06:47 2011 +0200
+++ b/Lib/textwrap.py	Tue Oct 11 14:57:01 2011 +0200
@@ -39,8 +39,11 @@
         of wrapped output; also counts towards each line's width.
       expand_tabs (default: true)
         Expand tabs in input text to spaces before further processing.
-        Each tab will become 1 .. 8 spaces, depending on its position in
-        its line.  If false, each tab is treated as a single character.
+        Each tab will become 0 .. 'tabsize' spaces, depending on its position
+        in its line.  If false, each tab is treated as a single character.
+      tabsize (default: 8)
+        Expand tabs in input text to 0 .. 'tabsize' spaces, unless
+        'expand_tabs' is false.
       replace_whitespace (default: true)
         Replace all whitespace characters in the input text by spaces
         after tab expansion.  Note that if expand_tabs is false and
@@ -96,6 +99,7 @@
                  initial_indent="",
                  subsequent_indent="",
                  expand_tabs=True,
+                 tabsize=8,
                  replace_whitespace=True,
                  fix_sentence_endings=False,
                  break_long_words=True,
@@ -105,6 +109,7 @@
         self.initial_indent = initial_indent
         self.subsequent_indent = subsequent_indent
         self.expand_tabs = expand_tabs
+        self.tabsize = tabsize
         self.replace_whitespace = replace_whitespace
         self.fix_sentence_endings = fix_sentence_endings
         self.break_long_words = break_long_words
@@ -123,7 +128,7 @@
         becomes " foo    bar  baz".
         """
         if self.expand_tabs:
-            text = text.expandtabs()
+            text = text.expandtabs(self.tabsize)
         if self.replace_whitespace:
             text = text.translate(self.unicode_whitespace_trans)
         return text