diff --git a/README.md b/README.md
index 48d0409..0d4557d 100644
--- a/README.md
+++ b/README.md
@@ -120,6 +120,14 @@ class <b>GraphqlPolicy</b>
 end
 </pre>
 
+With `graphql-ruby` gem version >= 1.8 and class-based type definitions, `type` doesn't return the actual type class [rmosolgo/graphql-ruby#1429](https://github.com/rmosolgo/graphql-ruby/issues/1429). To get the actual type class:
+
+<pre>
+def self.guard(type, field)
+  RULES.dig(<b>type.metadata[:type_class]</b>, field)
+end
+</pre>
+
 Pass this object to `GraphQL::Guard`:
 
 <pre>
diff --git a/spec/fixtures/policy_object_schema.rb b/spec/fixtures/policy_object_schema.rb
index c12bc5e..69bbda4 100644
--- a/spec/fixtures/policy_object_schema.rb
+++ b/spec/fixtures/policy_object_schema.rb
@@ -1,37 +1,75 @@
 # frozen_string_literal: true
 
 module PolicyObject
-  PostType = GraphQL::ObjectType.define do
-    name "Post"
-    field :id, !types.ID
-    field :title, types.String
-  end
+  case ENV['GRAPHQL_RUBY_VERSION']
+  when '1_7'
+    PostType = GraphQL::ObjectType.define do
+      name "Post"
+      field :id, !types.ID
+      field :title, types.String
+    end
 
-  QueryType = GraphQL::ObjectType.define do
-    name "Query"
-    field :posts, !types[!PostType] do
-      argument :userId, !types.ID
-      resolve ->(_obj, args, _ctx) { Post.where(user_id: args[:userId]) }
+    QueryType = GraphQL::ObjectType.define do
+      name "Query"
+      field :posts, !types[!PostType] do
+        argument :userId, !types.ID
+        resolve ->(_obj, args, _ctx) { Post.where(user_id: args[:userId]) }
+      end
     end
-  end
 
-  class GraphqlPolicy
-    RULES = {
-      QueryType => {
-        posts: ->(_obj, args, ctx) { args[:userId] == ctx[:current_user].id }
-      },
-      PostType => {
-        '*': ->(_post, args, ctx) { ctx[:current_user].admin? }
+    class GraphqlPolicy
+      RULES = {
+        QueryType => {
+          posts: ->(_obj, args, ctx) { args[:userId] == ctx[:current_user].id }
+        },
+        PostType => {
+          '*': ->(_post, args, ctx) { ctx[:current_user].admin? }
+        }
       }
-    }
 
-    def self.guard(type, field)
-      RULES.dig(type, field)
+      def self.guard(type, field)
+        RULES.dig(type, field)
+      end
     end
-  end
 
-  Schema = GraphQL::Schema.define do
-    query QueryType
-    use GraphQL::Guard.new(policy_object: GraphqlPolicy)
+    Schema = GraphQL::Schema.define do
+      query QueryType
+      use GraphQL::Guard.new(policy_object: GraphqlPolicy)
+    end
+  when '1_8'
+    class PostType < GraphQL::Schema::Object
+      field :id, ID, null: false
+      field :title, String, null: true
+    end
+
+    class QueryType < GraphQL::Schema::Object
+      field :posts, [PostType], null: false do
+        argument :user_id, ID, required: true
+      end
+
+      def posts(user_id:)
+        Post.where(user_id: user_id)
+      end
+    end
+
+    class GraphqlPolicy
+      RULES = {
+        QueryType => {
+          posts: ->(_obj, args, ctx) { args[:userId] == ctx[:current_user].id }
+        },
+        PostType => {
+          '*': ->(_post, args, ctx) { ctx[:current_user].admin? }
+        }
+      }
+
+      def self.guard(type, field)
+        RULES.dig(type.metadata[:type_class], field)
+      end
+    end
+
+    class Schema < GraphQL::Schema
+      query QueryType
+      use GraphQL::Guard.new(policy_object: GraphqlPolicy)
+    end
   end
 end
diff --git a/spec/graphql/testing_spec.rb b/spec/graphql/testing_spec.rb
index 23117e7..939c020 100644
--- a/spec/graphql/testing_spec.rb
+++ b/spec/graphql/testing_spec.rb
@@ -58,6 +58,7 @@
       }.to raise_error(GraphQL::Field::NoGuardError, "Guard lambda does not exist for Query.posts")
     end
 
+    if ENV['GRAPHQL_RUBY_VERSION'] == '1_7'
     it 'raises an error if the field was fetched without guard' do
       posts_field = PolicyObject::QueryType.get_field('posts')
       user = User.new(id: '1', role: 'admin')
@@ -66,6 +67,7 @@
         posts_field.guard(nil, {userId: user.id}, {current_user: user})
       }.to raise_error(GraphQL::Field::NoGuardError, "Get your field by calling: Type.field_with_guard('posts')")
     end
+    end
 
     it 'returns false for a not authorized field' do
       posts_field = PolicyObject::QueryType.field_with_guard('posts', PolicyObject::GraphqlPolicy)