diff --git a/packages/gatsby-source-wordpress/src/steps/create-schema-customization/build-types.js b/packages/gatsby-source-wordpress/src/steps/create-schema-customization/build-types.js
index bdce362fde9df..d5d30bfc87c67 100644
--- a/packages/gatsby-source-wordpress/src/steps/create-schema-customization/build-types.js
+++ b/packages/gatsby-source-wordpress/src/steps/create-schema-customization/build-types.js
@@ -9,7 +9,7 @@ import {
 } from "./helpers"
 
 const unionType = typeBuilderApi => {
-  const { typeDefs, schema, type, pluginOptions } = typeBuilderApi
+  const { schema, type, pluginOptions } = typeBuilderApi
 
   const types = type.possibleTypes
     .filter(
@@ -22,7 +22,7 @@ const unionType = typeBuilderApi => {
     .map(possibleType => buildTypeName(possibleType.name))
 
   if (!types || !types.length) {
-    return
+    return false
   }
 
   let unionType = {
@@ -47,13 +47,12 @@ const unionType = typeBuilderApi => {
   // @todo add this as a plugin option
   unionType = filterTypeDefinition(unionType, typeBuilderApi, `UNION`)
 
-  typeDefs.push(schema.buildUnionType(unionType))
+  return schema.buildUnionType(unionType)
 }
 
 const interfaceType = typeBuilderApi => {
   const {
     type,
-    typeDefs,
     schema,
     gatsbyNodeTypes,
     fieldAliases,
@@ -111,7 +110,7 @@ const interfaceType = typeBuilderApi => {
   // @todo add this as a plugin option
   typeDef = filterTypeDefinition(typeDef, typeBuilderApi, `INTERFACE`)
 
-  typeDefs.push(schema.buildInterfaceType(typeDef))
+  return schema.buildInterfaceType(typeDef)
 }
 
 const objectType = typeBuilderApi => {
@@ -120,7 +119,6 @@ const objectType = typeBuilderApi => {
     gatsbyNodeTypes,
     fieldAliases,
     fieldBlacklist,
-    typeDefs,
     schema,
     isAGatsbyNode,
   } = typeBuilderApi
@@ -138,7 +136,7 @@ const objectType = typeBuilderApi => {
   // TypeError: Cannot convert undefined or null to object at Function.keys (<anonymous>)
   // Also cause wordpress blog site build failure in createSchemaCustomization step
   if (!transformedFields || !Object.keys(transformedFields).length) {
-    return
+    return false
   }
 
   let objectType = {
@@ -180,21 +178,18 @@ const objectType = typeBuilderApi => {
   // @todo add this as a plugin option
   objectType = filterTypeDefinition(objectType, typeBuilderApi, `OBJECT`)
 
-  typeDefs.push(schema.buildObjectType(objectType))
+  return schema.buildObjectType(objectType)
 }
 
-const enumType = ({ typeDefs, schema, type }) => {
-  typeDefs.push(
-    schema.buildEnumType({
-      name: buildTypeName(type.name),
-      values: type.enumValues.reduce((accumulator, { name }) => {
-        accumulator[name] = { name }
-
-        return accumulator
-      }, {}),
-      description: type.description,
-    })
-  )
-}
+const enumType = ({ schema, type }) =>
+  schema.buildEnumType({
+    name: buildTypeName(type.name),
+    values: type.enumValues.reduce((accumulator, { name }) => {
+      accumulator[name] = { name }
+
+      return accumulator
+    }, {}),
+    description: type.description,
+  })
 
 export default { unionType, interfaceType, objectType, enumType }
diff --git a/packages/gatsby-source-wordpress/src/steps/create-schema-customization/helpers.js b/packages/gatsby-source-wordpress/src/steps/create-schema-customization/helpers.js
index 5e89e8979bae2..d08ab8ce82697 100644
--- a/packages/gatsby-source-wordpress/src/steps/create-schema-customization/helpers.js
+++ b/packages/gatsby-source-wordpress/src/steps/create-schema-customization/helpers.js
@@ -20,6 +20,10 @@ export const buildTypeName = name => {
     return name
   }
 
+  if (name === `Filter`) {
+    name = `FilterType`
+  }
+
   return prefix + name
 }
 
diff --git a/packages/gatsby-source-wordpress/src/steps/create-schema-customization/index.js b/packages/gatsby-source-wordpress/src/steps/create-schema-customization/index.js
index f5d593177fcba..e72877387a96f 100644
--- a/packages/gatsby-source-wordpress/src/steps/create-schema-customization/index.js
+++ b/packages/gatsby-source-wordpress/src/steps/create-schema-customization/index.js
@@ -42,18 +42,20 @@ const customizeSchema = async ({ actions, schema }) => {
       fieldOfTypeWasFetched(type) &&
       !typeIsExcluded({ pluginOptions, typeName: type.name })
     ) {
+      let builtType
+
       switch (type.kind) {
         case `UNION`:
-          buildType.unionType({ ...typeBuilderApi, type })
+          builtType = buildType.unionType({ ...typeBuilderApi, type })
           break
         case `INTERFACE`:
-          buildType.interfaceType({ ...typeBuilderApi, type })
+          builtType = buildType.interfaceType({ ...typeBuilderApi, type })
           break
         case `OBJECT`:
-          buildType.objectType({ ...typeBuilderApi, type })
+          builtType = buildType.objectType({ ...typeBuilderApi, type })
           break
         case `ENUM`:
-          buildType.enumType({ ...typeBuilderApi, type })
+          builtType = buildType.enumType({ ...typeBuilderApi, type })
           break
         case `SCALAR`:
           /**
@@ -62,6 +64,10 @@ const customizeSchema = async ({ actions, schema }) => {
            */
           break
       }
+
+      if (builtType) {
+        typeDefs.push(builtType)
+      }
     }
   })
 
@@ -69,7 +75,7 @@ const customizeSchema = async ({ actions, schema }) => {
   // where the typename is the type prefix
   // The node fields are the non-node root fields of the remote schema
   // like so: query { prefix { ...fields } }
-  buildType.objectType({
+  const wpType = buildType.objectType({
     ...typeBuilderApi,
     type: {
       kind: `OBJECT`,
@@ -81,6 +87,8 @@ const customizeSchema = async ({ actions, schema }) => {
     isAGatsbyNode: true,
   })
 
+  typeDefs.push(wpType)
+
   actions.createTypes(typeDefs)
 }