Index: Lib/zipfile.py
===================================================================
--- Lib/zipfile.py	(revision 55850)
+++ Lib/zipfile.py	(working copy)
@@ -252,6 +252,7 @@
             self.extract_version = max(45, self.extract_version)
             self.create_version = max(45, self.extract_version)
 
+        self._encodeFilename()
         header = struct.pack(structFileHeader, stringFileHeader,
                  self.extract_version, self.reserved, self.flag_bits,
                  self.compress_type, dostime, dosdate, CRC,
@@ -259,6 +260,16 @@
                  len(self.filename), len(extra))
         return header + self.filename + extra
 
+    def _encodeFilename(self):
+        if isinstance(self.filename, unicode):
+            self.filename = self.filename.encode('utf-8')
+            self.flag_bits = self.flag_bits | 0x800
+
+    def _decodeFilename(self):
+        if self.flag_bits & 0x800:
+            self.filename = self.filename.decode('utf-8')
+            self.flag_bits = self.flag_bits & ~0x800
+
     def _decodeExtra(self):
         # Try to decode the extra field.
         extra = self.extra
@@ -683,6 +694,7 @@
                                      t>>11, (t>>5)&0x3F, (t&0x1F) * 2 )
 
             x._decodeExtra()
+            x._decodeFilename()
             x.header_offset = x.header_offset + concat
             self.filelist.append(x)
             self.NameToInfo[x.filename] = x
@@ -967,6 +979,7 @@
                     extract_version = zinfo.extract_version
                     create_version = zinfo.create_version
 
+                zinfo._encodeFilename()
                 centdir = struct.pack(structCentralDir,
                   stringCentralDir, create_version,
                   zinfo.create_system, extract_version, zinfo.reserved,
Index: Lib/test/test_zipfile.py
===================================================================
--- Lib/test/test_zipfile.py	(revision 55850)
+++ Lib/test/test_zipfile.py	(working copy)
@@ -515,6 +515,11 @@
         # and report that the first file in the archive was corrupt.
         self.assertRaises(RuntimeError, zipf.testzip)
 
+    def testUnicodeFilenames(self):
+        zf = zipfile.ZipFile(TESTFN, "w")
+        zf.writestr(u"foo.txt", "Test for unicode filename")
+        zf.close()
+
     def tearDown(self):
         support.unlink(TESTFN)
         support.unlink(TESTFN2)