diff --git a/lib/absinthe/phase/schema/validation/input_output_types_correctly_placed.ex b/lib/absinthe/phase/schema/validation/input_output_types_correctly_placed.ex
index 442b7c55f5..7ea2b06a23 100644
--- a/lib/absinthe/phase/schema/validation/input_output_types_correctly_placed.ex
+++ b/lib/absinthe/phase/schema/validation/input_output_types_correctly_placed.ex
@@ -9,7 +9,7 @@ defmodule Absinthe.Phase.Schema.Validation.InputOutputTypesCorrectlyPlaced do
 
   defp handle_schemas(%Blueprint.Schema.SchemaDefinition{} = schema) do
     types = Map.new(schema.type_definitions, &{&1.identifier, &1})
-    schema = Blueprint.prewalk(schema, &validate_type(&1, types))
+    schema = Blueprint.prewalk(schema, &validate_type(&1, types, schema))
     {:halt, schema}
   end
 
@@ -17,8 +17,12 @@ defmodule Absinthe.Phase.Schema.Validation.InputOutputTypesCorrectlyPlaced do
     obj
   end
 
-  defp validate_type(%Blueprint.Schema.InputValueDefinition{} = arg, types) do
-    arg_type = Map.get(types, Blueprint.TypeReference.unwrap(arg.type))
+  defp validate_type(%Blueprint.Schema.InputValueDefinition{} = arg, types, schema) do
+    type =
+      Blueprint.TypeReference.unwrap(arg.type)
+      |> Blueprint.TypeReference.to_type(schema)
+
+    arg_type = Map.get(types, type)
 
     if arg_type && wrong_type?(Blueprint.Schema.InputValueDefinition, arg_type) do
       detail = %{
@@ -33,11 +37,15 @@ defmodule Absinthe.Phase.Schema.Validation.InputOutputTypesCorrectlyPlaced do
     end
   end
 
-  defp validate_type(%struct{fields: fields} = type, types) do
+  defp validate_type(%struct{fields: fields} = type, types, schema) do
     fields =
       Enum.map(fields, fn
         %{type: _} = field ->
-          field_type = Map.get(types, Blueprint.TypeReference.unwrap(field.type))
+          type =
+            Blueprint.TypeReference.unwrap(field.type)
+            |> Blueprint.TypeReference.to_type(schema)
+
+          field_type = Map.get(types, type)
 
           if field_type && wrong_type?(struct, field_type) do
             detail = %{
@@ -59,7 +67,7 @@ defmodule Absinthe.Phase.Schema.Validation.InputOutputTypesCorrectlyPlaced do
     %{type | fields: fields}
   end
 
-  defp validate_type(type, _types) do
+  defp validate_type(type, _types, _schema) do
     type
   end
 
diff --git a/test/absinthe/schema/rule/input_output_types_correctly_placed_test.exs b/test/absinthe/schema/rule/input_output_types_correctly_placed_test.exs
index fe861c6c45..18e7dd6999 100644
--- a/test/absinthe/schema/rule/input_output_types_correctly_placed_test.exs
+++ b/test/absinthe/schema/rule/input_output_types_correctly_placed_test.exs
@@ -1,7 +1,7 @@
 defmodule Absinthe.Schema.Rule.InputOutputTypesCorrectlyPlacedTest do
   use Absinthe.Case, async: true
 
-  describe "rule" do
+  describe "macro schema" do
     test "is enforced with output types on arguments" do
       assert_schema_error("invalid_output_types", [
         %{
@@ -56,4 +56,74 @@ defmodule Absinthe.Schema.Rule.InputOutputTypesCorrectlyPlacedTest do
       ])
     end
   end
+
+  describe "sdl schema" do
+    test "is enforced with output types on arguments" do
+      assert_schema_error("invalid_output_types_sdl", [
+        %{
+          extra: %{
+            field: :blah,
+            parent: Absinthe.Blueprint.Schema.ObjectTypeDefinition,
+            struct: Absinthe.Blueprint.Schema.InputObjectTypeDefinition,
+            type: :input
+          },
+          locations: [
+            %{
+              file: "test/support/fixtures/dynamic/invalid_output_types_sdl.exs",
+              line: 4
+            }
+          ],
+          phase: Absinthe.Phase.Schema.Validation.InputOutputTypesCorrectlyPlaced
+        },
+        %{
+          extra: %{
+            argument: :invalid_arg,
+            struct: Absinthe.Blueprint.Schema.ObjectTypeDefinition,
+            type: :user
+          },
+          locations: [
+            %{
+              file: "test/support/fixtures/dynamic/invalid_output_types_sdl.exs",
+              line: 4
+            }
+          ],
+          phase: Absinthe.Phase.Schema.Validation.InputOutputTypesCorrectlyPlaced
+        }
+      ])
+    end
+
+    test "is enforced with input types on arguments" do
+      assert_schema_error("invalid_input_types_sdl", [
+        %{
+          extra: %{
+            argument: :blah,
+            struct: Absinthe.Blueprint.Schema.ObjectTypeDefinition,
+            type: :user
+          },
+          locations: [
+            %{
+              file: "test/support/fixtures/dynamic/invalid_input_types_sdl.exs",
+              line: 4
+            }
+          ],
+          phase: Absinthe.Phase.Schema.Validation.InputOutputTypesCorrectlyPlaced
+        },
+        %{
+          extra: %{
+            field: :blah,
+            parent: Absinthe.Blueprint.Schema.InputObjectTypeDefinition,
+            struct: Absinthe.Blueprint.Schema.ObjectTypeDefinition,
+            type: :user
+          },
+          locations: [
+            %{
+              file: "test/support/fixtures/dynamic/invalid_input_types_sdl.exs",
+              line: 4
+            }
+          ],
+          phase: Absinthe.Phase.Schema.Validation.InputOutputTypesCorrectlyPlaced
+        }
+      ])
+    end
+  end
 end
diff --git a/test/support/fixtures/dynamic/invalid_input_types_sdl.exs b/test/support/fixtures/dynamic/invalid_input_types_sdl.exs
new file mode 100644
index 0000000000..0f87f2dc77
--- /dev/null
+++ b/test/support/fixtures/dynamic/invalid_input_types_sdl.exs
@@ -0,0 +1,15 @@
+defmodule Absinthe.Fixtures.InvalidOutputTypesSdlSchema do
+  use Absinthe.Schema
+
+  import_sdl """
+    type User
+
+    input Foo {
+      blah: User
+    }
+
+    type Query {
+      foo(arg: Foo): User
+    }
+  """
+end
diff --git a/test/support/fixtures/dynamic/invalid_output_types_sdl.exs b/test/support/fixtures/dynamic/invalid_output_types_sdl.exs
new file mode 100644
index 0000000000..c313726e4b
--- /dev/null
+++ b/test/support/fixtures/dynamic/invalid_output_types_sdl.exs
@@ -0,0 +1,17 @@
+defmodule Absinthe.Fixtures.InvalidInputTypesSdlSchema do
+  use Absinthe.Schema
+
+  import_sdl """
+    type User
+
+    input Input
+
+    type BadObject {
+      blah: Input
+    }
+
+    type Query {
+      foo(invalidArg: User): User
+    }
+  """
+end