Index: bindings/python/tests/cindex/test_translation_unit.py
===================================================================
--- bindings/python/tests/cindex/test_translation_unit.py
+++ bindings/python/tests/cindex/test_translation_unit.py
@@ -93,12 +93,9 @@
         self.assertEqual(spellings[-1], 'y')
 
     def test_unsaved_files_2(self):
-        try:
-            from StringIO import StringIO
-        except:
-            from io import StringIO
+        from io import BytesIO
         tu = TranslationUnit.from_source('fake.c', unsaved_files = [
-                ('fake.c', StringIO('int x;'))])
+                ('fake.c', BytesIO('int x;'))])
         spellings = [c.spelling for c in tu.cursor.get_children()]
         self.assertEqual(spellings[-1], 'x')
 
Index: tools/clang-format/clang-format-diff.py
===================================================================
--- tools/clang-format/clang-format-diff.py
+++ tools/clang-format/clang-format-diff.py
@@ -28,10 +28,11 @@
 import re
 import subprocess
 import sys
-try:
-  from StringIO import StringIO
-except ImportError:
-   from io import StringIO
+
+if sys.version_info.major == 3:
+    from io import StringIO
+else:
+    from io import BytesIO as StringIO
 
 
 def main():
Index: tools/scan-view/share/ScanView.py
===================================================================
--- tools/scan-view/share/ScanView.py
+++ tools/scan-view/share/ScanView.py
@@ -13,7 +13,12 @@
     from urllib.parse import urlparse, unquote
 
 import posixpath
-import StringIO
+
+if sys.version_info.major == 3:
+    from io import StringIO, BytesIO
+else:
+    from io import BytesIO, BytesIO as StringIO
+
 import re
 import shutil
 import threading
@@ -117,7 +122,7 @@
         except Reporter.ReportFailure as e:
             self.status = e.value
         except Exception as e:
-            s = StringIO.StringIO()
+            s = StringIO()
             import traceback
             print('<b>Unhandled Exception</b><br><pre>', file=s)
             traceback.print_exc(file=s)
@@ -275,12 +280,12 @@
 
     def handle_exception(self, exc):
         import traceback
-        s = StringIO.StringIO()
+        s = StringIO()
         print("INTERNAL ERROR\n", file=s)
         traceback.print_exc(file=s)
         f = self.send_string(s.getvalue(), 'text/plain')
         if f:
-            self.copyfile(f, self.wfile)
+            self.copyfile(BytesIO(f.getvalue().encode()), self.wfile)
             f.close()        
             
     def get_scalar_field(self, name):
@@ -739,15 +744,16 @@
         return f
 
     def send_string(self, s, ctype='text/html', headers=True, mtime=None):
+        encoded_s = s.encode()
         if headers:
             self.send_response(200)
             self.send_header("Content-type", ctype)
-            self.send_header("Content-Length", str(len(s)))
+            self.send_header("Content-Length", str(len(encoded_s)))
             if mtime is None:
                 mtime = self.dynamic_mtime
             self.send_header("Last-Modified", self.date_time_string(mtime))
             self.end_headers()
-        return StringIO.StringIO(s)
+        return BytesIO(encoded_s)
 
     def send_patched_file(self, path, ctype):
         # Allow a very limited set of variables. This is pretty gross.