diff --git a/AUTHORS.rst b/AUTHORS.rst
index 5ed19015..3dde015f 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -32,6 +32,7 @@ Patches and suggestions
 - Andreas Madsack
 - Karim Valiev
 - Marc DM
+- Ritwik Gupta
 - Tony Lopes
 - lilbludevil
 - Simon Sapin
diff --git a/CHANGES.rst b/CHANGES.rst
index f2591d2f..047a7545 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,6 +4,7 @@ Change Log
 unreleased
 ~~~~~~~~~~~~~~~~~~
 
+* Added the seamless attribute for iframes.
 * Added `itemscope` as boolean attribute 
   https://github.com/html5lib/html5lib-python/issues/194
 
diff --git a/html5lib/constants.py b/html5lib/constants.py
index 975aa021..5c6f5558 100644
--- a/html5lib/constants.py
+++ b/html5lib/constants.py
@@ -606,6 +606,7 @@
     "input": frozenset(["disabled", "readonly", "required", "autofocus", "checked", "ismap"]),
     "select": frozenset(["disabled", "readonly", "autofocus", "multiple"]),
     "output": frozenset(["disabled", "readonly"]),
+    "iframe": frozenset(["seamless"]),
 }
 
 # entitiesWindows1252 has to be _ordered_ and needs to have an index. It