diff --git a/lib/resource/resource.ex b/lib/resource/resource.ex
index 1fc0e87d..d34d1e8f 100644
--- a/lib/resource/resource.ex
+++ b/lib/resource/resource.ex
@@ -2454,13 +2454,24 @@ defmodule AshGraphql.Resource do
                     identifier: name,
                     __reference__: AshGraphql.Resource.ref(env),
                     name: to_string(name),
-                    type: nested_type_name
+                    type:
+                      if Keyword.get(
+                           attribute,
+                           :allow_nil?,
+                           true
+                         ) do
+                        nested_type_name
+                      else
+                        %Absinthe.Blueprint.TypeReference.NonNull{
+                          of_type: nested_type_name
+                        }
+                      end
                   }
                   | fields
                 ]
               }
 
-            _ ->
+            {type, _} ->
               {types,
                [
                  %Absinthe.Blueprint.Schema.FieldDefinition{
@@ -2468,7 +2479,18 @@ defmodule AshGraphql.Resource do
                    identifier: name,
                    __reference__: AshGraphql.Resource.ref(env),
                    name: to_string(name),
-                   type: do_field_type(attribute[:type], nil, nil, false)
+                   type:
+                     if Keyword.get(
+                          attribute,
+                          :allow_nil?,
+                          true
+                        ) do
+                       do_field_type(type, nil, nil, false)
+                     else
+                       %Absinthe.Blueprint.TypeReference.NonNull{
+                         of_type: do_field_type(type, nil, nil, false)
+                       }
+                     end
                  }
                  | fields
                ]}
@@ -2515,13 +2537,20 @@ defmodule AshGraphql.Resource do
                     identifier: name,
                     __reference__: AshGraphql.Resource.ref(env),
                     name: to_string(name),
-                    type: nested_type_name
+                    type:
+                      if Keyword.get(attribute, :allow_nil?, true) do
+                        nested_type_name
+                      else
+                        %Absinthe.Blueprint.TypeReference.NonNull{
+                          of_type: nested_type_name
+                        }
+                      end
                   }
                   | fields
                 ]
               }
 
-            _ ->
+            {type, _} ->
               {types,
                [
                  %Absinthe.Blueprint.Schema.InputValueDefinition{
@@ -2529,7 +2558,14 @@ defmodule AshGraphql.Resource do
                    identifier: name,
                    __reference__: AshGraphql.Resource.ref(env),
                    name: to_string(name),
-                   type: do_field_type(attribute[:type], nil, nil, false)
+                   type:
+                     if Keyword.get(attribute, :allow_nil?, true) do
+                       do_field_type(type, nil, nil, false)
+                     else
+                       %Absinthe.Blueprint.TypeReference.NonNull{
+                         of_type: do_field_type(type, nil, nil, false)
+                       }
+                     end
                  }
                  | fields
                ]}
diff --git a/test/attribute_test.exs b/test/attribute_test.exs
index 84e84d5c..e23e667d 100644
--- a/test/attribute_test.exs
+++ b/test/attribute_test.exs
@@ -157,8 +157,11 @@ defmodule AshGraphql.AttributeTest do
       data["__type"]["inputFields"]
       |> Enum.find(fn field -> field["name"] == "foo" end)
 
-    assert foo_field["type"]["kind"] == "SCALAR"
-    assert foo_field["type"]["name"] == "String"
+    # non null field
+    assert foo_field["type"]["kind"] == "NON_NULL"
+
+    assert foo_field["type"]["ofType"]["kind"] == "SCALAR"
+    assert foo_field["type"]["ofType"]["name"] == "String"
 
     bar_field =
       data["__type"]["inputFields"]
@@ -257,7 +260,11 @@ defmodule AshGraphql.AttributeTest do
                     },
                     %{
                       "name" => "fooBar",
-                      "type" => %{"kind" => "SCALAR", "name" => "String", "ofType" => nil}
+                      "type" => %{
+                        "kind" => "NON_NULL",
+                        "name" => nil,
+                        "ofType" => %{"kind" => "SCALAR", "name" => "String"}
+                      }
                     }
                   ]
                 }
@@ -301,7 +308,11 @@ defmodule AshGraphql.AttributeTest do
                     },
                     %{
                       "name" => "fooBar",
-                      "type" => %{"kind" => "SCALAR", "name" => "String", "ofType" => nil}
+                      "type" => %{
+                        "kind" => "NON_NULL",
+                        "name" => nil,
+                        "ofType" => %{"kind" => "SCALAR", "name" => "String"}
+                      }
                     }
                   ]
                 }
diff --git a/test/support/resources/map_types.ex b/test/support/resources/map_types.ex
index 361ea8d5..f11ae12c 100644
--- a/test/support/resources/map_types.ex
+++ b/test/support/resources/map_types.ex
@@ -11,7 +11,8 @@ defmodule AshGraphql.Test.MapTypes do
       constraints(
         fields: [
           foo: [
-            type: :string
+            type: :string,
+            allow_nil?: false
           ],
           bar: [
             type: :integer
@@ -39,7 +40,8 @@ defmodule AshGraphql.Test.MapTypes do
         constraints(
           fields: [
             foo: [
-              type: :string
+              type: :string,
+              allow_nil?: false
             ],
             bar: [
               type: :integer