diff --git a/src/Data/Gram/Arbitrary.hs b/src/Data/Gram/Arbitrary.hs
index af0820575..960de3525 100644
--- a/src/Data/Gram/Arbitrary.hs
+++ b/src/Data/Gram/Arbitrary.hs
@@ -1,2 +1,9 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
 module Data.Gram.Arbitrary where
 
+import Data.Gram
+import Prologue
+import Test.QuickCheck
+
+instance Arbitrary label => Arbitrary (Gram label) where
+  arbitrary = Gram <$> arbitrary <*> arbitrary