diff --git a/packages/better-fetch/src/create-fetch/types.ts b/packages/better-fetch/src/create-fetch/types.ts
index 599036c..f06d221 100644
--- a/packages/better-fetch/src/create-fetch/types.ts
+++ b/packages/better-fetch/src/create-fetch/types.ts
@@ -83,7 +83,7 @@ export type InferHeaders<H> = H extends StandardSchemaV1
 	: Record<string, string>;
 
 export type IsFieldOptional<T> = T extends StandardSchemaV1
-	? undefined extends T
+	? undefined extends StandardSchemaV1.InferInput<T>
 		? true
 		: false
 	: true;
diff --git a/packages/better-fetch/src/test/create.test.ts b/packages/better-fetch/src/test/create.test.ts
index 3c4dbe7..36c75a8 100644
--- a/packages/better-fetch/src/test/create.test.ts
+++ b/packages/better-fetch/src/test/create.test.ts
@@ -183,6 +183,28 @@ describe("create-fetch-runtime-test", () => {
 		});
 	});
 
+	it("applies a default query when options are omitted", async () => {
+		let requestQuery: unknown;
+		const fetch = createFetch({
+			baseURL: "https://example.com",
+			schema: createSchema({
+				"/movies": {
+					query: z
+						.object({ include: z.array(z.string()) })
+						.default({ include: ["recommendations"] }),
+				},
+			}),
+			customFetchImpl: async () => new Response(),
+			onRequest(context) {
+				requestQuery = context.query;
+			},
+		});
+
+		await fetch("/movies");
+
+		expect(requestQuery).toEqual({ include: ["recommendations"] });
+	});
+
 	it("should validate response and return data if validation passes", async () => {
 		const res = await $fetch("/echo", {
 			output: z.object({