diff --git a/packages/strapi-plugin-graphql/services/GraphQL.js b/packages/strapi-plugin-graphql/services/GraphQL.js
index 7fde6f9a9e..a85430cd70 100644
--- a/packages/strapi-plugin-graphql/services/GraphQL.js
+++ b/packages/strapi-plugin-graphql/services/GraphQL.js
@@ -533,7 +533,10 @@ module.exports = {
 
                 const entry = withRelated && withRelated.toJSON ? withRelated.toJSON() : withRelated;
 
-                entry[association.alias]._type = _.upperFirst(association.model);
+                // Set the _type only when the value is defined
+                if (entry[association.alias]) {
+                  entry[association.alias]._type = _.upperFirst(association.model);
+                }
 
                 return entry[association.alias];
               }