diff --git a/json-spec-elm.cabal b/json-spec-elm.cabal
--- a/json-spec-elm.cabal
+++ b/json-spec-elm.cabal
@@ -1,6 +1,6 @@
 cabal-version:       3.0
 name:                json-spec-elm
-version:             0.3.0.1
+version:             0.3.0.2
 synopsis:            Elm code generate for `json-spec`.
 description:         
                      Produce elm types, encoders, and decoders from a
diff --git a/src/Data/JsonSpec/Elm.hs b/src/Data/JsonSpec/Elm.hs
--- a/src/Data/JsonSpec/Elm.hs
+++ b/src/Data/JsonSpec/Elm.hs
@@ -276,7 +276,7 @@
       Expr.Lam . toScope $
         Expr.apps
           "Maybe.withDefault"
-          [ "Json.Decode.null"
+          [ "Json.Encode.null"
           , Expr.apps
               "Maybe.map"
               [ Expr.bind Expr.Global absurd encoder
diff --git a/test/test.hs b/test/test.hs
--- a/test/test.hs
+++ b/test/test.hs
@@ -7,7 +7,7 @@
 import Data.Foldable (traverse_)
 import Data.HashMap.Strict (HashMap)
 import Data.JsonSpec (Specification(JsonArray, JsonDateTime, JsonEither,
-  JsonInt, JsonLet, JsonNum, JsonObject, JsonRef, JsonString, JsonTag))
+  JsonInt, JsonLet, JsonNullable, JsonNum, JsonObject, JsonRef, JsonString, JsonTag))
 import Data.JsonSpec.Elm (Named, elmDefs)
 import Data.Maybe (fromMaybe)
 import Data.Proxy (Proxy(Proxy))
@@ -200,7 +200,51 @@
             \)"
           callCommand "rm -rf elm-test"
 
+      it "works with nullable values" $
+        let
+          actual :: HashMap Module Text
+          actual =
+            fmap ((<> "\n") . renderStrict . layoutPretty defaultLayoutOptions)
+            . modules
+            . Set.toList
+            $ elmDefs (Proxy @NullableSpec)
 
+          expected :: HashMap Module Text
+          expected = 
+            HM.singleton
+              ["Api", "Data"]
+              ( Text.unlines
+                  [ "module Api.Data exposing"
+                  , "    ( nullableIntDecoder"
+                  , "    , nullableIntEncoder"
+                  , "    , NullableInt"
+                  , "    )"
+                  , ""
+                  , "import Json.Decode"
+                  , "import Json.Encode"
+                  , ""
+                  , ""
+                  , "nullableIntDecoder : Json.Decode.Decoder NullableInt"
+                  , "nullableIntDecoder ="
+                  , "    Json.Decode.nullable Json.Decode.int"
+                  , ""
+                  , ""
+                  , "nullableIntEncoder : NullableInt -> Json.Encode.Value"
+                  , "nullableIntEncoder a ="
+                  , "    Maybe.withDefault Json.Encode.null (Maybe.map Json.Encode.int a)"
+                  , ""
+                  , ""
+                  , "type alias NullableInt  ="
+                  , "    Maybe Int"
+                  ]
+              )
+        in do
+          TIO.hPutStrLn stderr "==========================================\n\n"
+          TIO.hPutStrLn stderr (fromMaybe "" (HM.lookup ["Api", "Data"] actual))
+          TIO.hPutStrLn stderr "\n\n==========================================\n\n"
+          actual `shouldBe` expected
+
+
 {-
   This spec is copied from an as-yet uncompleted personal project. I
   just used it because it is fairly complex. Probably something known
@@ -311,6 +355,9 @@
          ]
     )
 
+type NullableSpec =
+  Named "NullableInt"
+    (JsonNullable JsonInt)
 
 writeModule :: (Module, Text) -> IO ()
 writeModule (module_, content) = do