diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index d0ed6df3e2..cf8d920989 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -6,16 +6,35 @@ Requires cx_Oracle: http://cx-oracle.sourceforge.net/
 
 
 import datetime
-import os
 import sys
 import time
 from decimal import Decimal
 
-# Oracle takes client-side character set encoding from the environment.
-os.environ['NLS_LANG'] = '.UTF8'
-# This prevents unicode from getting mangled by getting encoded into the
-# potentially non-unicode database character set.
-os.environ['ORA_NCHAR_LITERAL_REPLACE'] = 'TRUE'
+
+def _setup_environment(environ):
+    import platform
+    # Cygwin requires some special voodoo to set the environment variables
+    # properly so that Oracle will see them.
+    if platform.system().upper().startswith('CYGWIN'):
+        try:
+            import ctypes
+        except ImportError:
+            raise ImportError("ctypes not found. The Oracle backend requires ctypes to operate correctly under Cygwin.")
+        kernel32 = ctypes.CDLL('kernel32')
+        for name, value in environ:
+            kernel32.SetEnvironmentVariableA(name, value)
+    else:
+        import os
+        os.environ.update(environ)
+
+_setup_environment([
+    # Oracle takes client-side character set encoding from the environment.
+    ('NLS_LANG', '.UTF8'),
+    # This prevents unicode from getting mangled by getting encoded into the
+    # potentially non-unicode database character set.
+    ('ORA_NCHAR_LITERAL_REPLACE', 'TRUE'),
+])
+
 
 try:
     import cx_Oracle as Database