diff -r 65a2b468fb3c Lib/zipapp.py
--- a/Lib/zipapp.py	Fri Mar 13 10:42:08 2015 -0400
+++ b/Lib/zipapp.py	Fri Mar 13 11:10:18 2015 -0400
@@ -36,6 +36,8 @@
 
 @contextlib.contextmanager
 def _maybe_open(archive, mode):
+    if isinstance(archive, pathlib.Path):
+        archive = str(archive)
     if isinstance(archive, str):
         with open(archive, mode) as f:
             yield f
@@ -92,12 +94,20 @@
     is an error to omit MAIN if the directory has no __main__.py.
     """
     # Are we copying an existing archive?
-    if not (isinstance(source, str) and os.path.isdir(source)):
+    source_exists = False
+    if hasattr(source, 'read') and hasattr(source, 'readline'):
+        source_exists = True
+    else:
+        source = pathlib.Path(source)
+        if source.is_file():
+            source_exists = True
+
+    if source_exists:
         _copy_archive(source, target, interpreter)
         return
 
-    # We are creating a new archive from a directory
-    has_main = os.path.exists(os.path.join(source, '__main__.py'))
+    # We are creating a new archive from a directory.
+    has_main = (source / '__main__.py').exists()
     if main and has_main:
         raise ZipAppError(
             "Cannot specify entry point if the source has __main__.py")
@@ -106,7 +116,7 @@
 
     main_py = None
     if main:
-        # Check that main has the right format
+        # Check that main has the right format.
         mod, sep, fn = main.partition(':')
         mod_ok = all(part.isidentifier() for part in mod.split('.'))
         fn_ok = all(part.isidentifier() for part in fn.split('.'))
@@ -115,7 +125,9 @@
         main_py = MAIN_TEMPLATE.format(module=mod, fn=fn)
 
     if target is None:
-        target = source + '.pyz'
+        target = source.with_suffix('.pyz')
+    elif not hasattr(target, 'write'):
+        target = pathlib.Path(target)
 
     with _maybe_open(target, 'wb') as fd:
         _write_file_prefix(fd, interpreter)
@@ -127,8 +139,8 @@
             if main_py:
                 z.writestr('__main__.py', main_py.encode('utf-8'))
 
-    if interpreter and isinstance(target, str):
-        os.chmod(target, os.stat(target).st_mode | stat.S_IEXEC)
+    if interpreter and not hasattr(target, 'write'):
+        target.chmod(target.stat().st_mode | stat.S_IEXEC)
 
 
 def get_interpreter(archive):