diff --git a/.changeset/eighty-trees-confess.md b/.changeset/eighty-trees-confess.md
new file mode 100644
index 00000000000..1ced43cffcb
--- /dev/null
+++ b/.changeset/eighty-trees-confess.md
@@ -0,0 +1,5 @@
+---
+'@graphql-codegen/typescript': major
+---
+
+handle undefined namedType when including introspection type definitions
diff --git a/packages/plugins/typescript/typescript/src/index.ts b/packages/plugins/typescript/typescript/src/index.ts
index 2baf4ac887f..342bc3308cf 100644
--- a/packages/plugins/typescript/typescript/src/index.ts
+++ b/packages/plugins/typescript/typescript/src/index.ts
@@ -65,7 +65,7 @@ export function includeIntrospectionTypesDefinitions(
     Field() {
       const type = getNamedType(typeInfo.getType());
 
-      if (isIntrospectionType(type) && !usedTypes.includes(type)) {
+      if (type && isIntrospectionType(type) && !usedTypes.includes(type)) {
         usedTypes.push(type);
       }
     },