diff --git a/env.py b/env.py
index 87176b1..59f8402 100644
--- a/env.py
+++ b/env.py
@@ -12,7 +12,7 @@ def lower_dict(d):
 
     _d = {}
 
-    for k, v in d.iteritems():
+    for k, v in d.items():
         try:
             _d[k.lower()] = v
         except AttributeError:
@@ -45,7 +45,7 @@ def prefix(prefix):
 
     prefix = prefix.lower()
 
-    for k, v in e.iteritems():
+    for k, v in e.items():
         try:
             if k.startswith(prefix):
                 k = k[len(prefix):]
@@ -64,7 +64,7 @@ def map(**kwargs):
     d = {}
     e = lower_dict(environ.copy())
 
-    for k, v in kwargs.iteritems():
+    for k, v in kwargs.items():
         d[k] = e.get(v.lower())
 
     return d