diff --git a/optional-args.cabal b/optional-args.cabal
--- a/optional-args.cabal
+++ b/optional-args.cabal
@@ -1,5 +1,5 @@
 Name: optional-args
-Version: 1.0.1
+Version: 1.0.2
 Cabal-Version: >=1.10
 Build-Type: Simple
 License: BSD3
@@ -21,6 +21,8 @@
 Library
     HS-Source-Dirs: src
     Build-Depends: base >= 4.5 && < 5
+    if !impl(ghc >= 8.0)
+      Build-Depends: semigroups >= 0.16 && < 0.19
     Exposed-Modules: Data.Optional
     GHC-Options: -O2 -Wall
     Default-Language: Haskell2010
diff --git a/src/Data/Optional.hs b/src/Data/Optional.hs
--- a/src/Data/Optional.hs
+++ b/src/Data/Optional.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP               #-}
 {-# LANGUAGE DeriveFunctor     #-}
 {-# LANGUAGE DeriveFoldable    #-}
 {-# LANGUAGE DeriveTraversable #-}
@@ -97,6 +98,7 @@
 import Data.Foldable (Foldable)
 import Data.Traversable (Traversable)
 import Data.Monoid (Monoid(..))
+import Data.Semigroup (Semigroup(..))
 import Data.String (IsString(..))
 
 -- | A function argument that has a `Default` value
@@ -125,10 +127,15 @@
     mzero = empty
     mplus = (<|>)
 
+instance Semigroup a => Semigroup (Optional a) where
+    (<>) = liftA2 (<>)
+
 instance Monoid a => Monoid (Optional a) where
     mempty = pure mempty
 
+#if !(MIN_VERSION_base(4,11,0))
     mappend = liftA2 mappend
+#endif
 
 instance IsString a => IsString (Optional a) where
     fromString str = pure (fromString str)