diff --git a/src/utilities/__tests__/buildASTSchema-test.js b/src/utilities/__tests__/buildASTSchema-test.js
index 39f127bbcc..e0578b0f34 100644
--- a/src/utilities/__tests__/buildASTSchema-test.js
+++ b/src/utilities/__tests__/buildASTSchema-test.js
@@ -743,7 +743,7 @@ describe('Schema Builder', () => {
         field2: Int @deprecated(reason: "Because I said so")
         enum: MyEnum
         field3(oldArg: String @deprecated, arg: String): String
-        field4(oldArg: String @deprecated(reason: "why not?"), arg: String): String
+        field4(oldArg: String @deprecated(reason: "Why not?"), arg: String): String
         field5(arg: MyInput): String
       }
     `;
diff --git a/src/utilities/extendSchema.js b/src/utilities/extendSchema.js
index 9f24b6eec4..b262df677a 100644
--- a/src/utilities/extendSchema.js
+++ b/src/utilities/extendSchema.js
@@ -501,6 +501,7 @@ export function extendSchemaImpl(
         type,
         description: getDescription(arg, options),
         defaultValue: valueFromAST(arg.defaultValue, type),
+        deprecationReason: getDeprecationReason(arg),
         astNode: arg,
       };
     }