diff --git a/stacker/lookups/handlers/kms.py b/stacker/lookups/handlers/kms.py
index ba80d2779..922fd311f 100644
--- a/stacker/lookups/handlers/kms.py
+++ b/stacker/lookups/handlers/kms.py
@@ -64,4 +64,4 @@ def handle(cls, value, **kwargs):
         decoded = codecs.decode(value, 'base64')
 
         # decrypt and return the plain text raw value.
-        return kms.decrypt(CiphertextBlob=decoded)["Plaintext"]
+        return kms.decrypt(CiphertextBlob=decoded)["Plaintext"].decode('utf-8')