diff --git a/yesod-core/Yesod/Core/Types.hs b/yesod-core/Yesod/Core/Types.hs
index a8605665..4ee00694 100644
--- a/yesod-core/Yesod/Core/Types.hs
+++ b/yesod-core/Yesod/Core/Types.hs
@@ -65,6 +65,7 @@ import Yesod.Core.TypeCache (TypeMap, KeyedTypeMap)
 #if MIN_VERSION_monad_logger(0, 3, 10)
 import Control.Monad.Logger (MonadLoggerIO (..))
 #endif
+import Data.Semigroup (Semigroup)
 
 -- Sessions
 type SessionMap = Map Text ByteString
@@ -248,6 +249,7 @@ newtype WidgetT site m a = WidgetT
 instance (a ~ (), Monad m) => Monoid (WidgetT site m a) where
     mempty = return ()
     mappend x y = x >> y
+instance (a ~ (), Monad m) => Semigroup (WidgetT site m a)
 
 type RY master = Route master -> [(Text, Text)] -> Text
 
diff --git a/yesod-core/yesod-core.cabal b/yesod-core/yesod-core.cabal
index c8f1070a..4a879904 100644
--- a/yesod-core/yesod-core.cabal
+++ b/yesod-core/yesod-core.cabal
@@ -68,6 +68,7 @@ library
                    , primitive
                    , word8
                    , auto-update
+                   , semigroups
 
     exposed-modules: Yesod.Core
                      Yesod.Core.Content