diff --git a/packages/zod/src/index.ts b/packages/zod/src/index.ts
index a7c4865db..de90cace0 100644
--- a/packages/zod/src/index.ts
+++ b/packages/zod/src/index.ts
@@ -281,7 +281,14 @@ export const generateZodValidationSchemaDefinition = (
     }
 
     if (typeof siblingSchema.description === 'string') {
-      functions.push(['describe', `"${escape(siblingSchema.description)}"`]);
+      // Use the same single-quoted, fully JS-escaped form as the primitive
+      // description path (see `pushDescriptionOrMeta`). `escape` only escapes
+      // quote chars, so a multi-line description would emit raw newlines and
+      // break the generated string literal (TS1002).
+      functions.push([
+        'describe',
+        `'${jsStringEscape(siblingSchema.description)}'`,
+      ]);
     }
   };
 
diff --git a/packages/zod/src/zod.test.ts b/packages/zod/src/zod.test.ts
index f43ab0ffb..06e23b27a 100644
--- a/packages/zod/src/zod.test.ts
+++ b/packages/zod/src/zod.test.ts
@@ -4078,7 +4078,33 @@ describe('generateZodValidationSchemaDefinition`', () => {
       );
       expect(result.functions).toEqual([
         ['namedRef', { name: 'Pet', sourceRef: '#/components/schemas/Pet' }],
-        ['describe', '"optional pet"'],
+        ['describe', "'optional pet'"],
+      ]);
+    });
+
+    it('escapes newlines in a multi-line description sibling on a $ref (#3517)', () => {
+      const context = makeContextSpec({
+        spec: { components: { schemas: { Pet: { type: 'object' } } } },
+      });
+      const result = generateZodValidationSchemaDefinition(
+        {
+          $ref: '#/components/schemas/Pet',
+          description: 'Subject identifier.\n\nMust be normalized first.',
+        } as never,
+        context,
+        'someField',
+        false,
+        false,
+        { required: true, useReusableSchemas: true },
+      );
+      // Same single-quoted, \n-escaped form as a primitive sibling — no raw
+      // newlines that would break the generated string literal (TS1002).
+      expect(result.functions).toEqual([
+        ['namedRef', { name: 'Pet', sourceRef: '#/components/schemas/Pet' }],
+        [
+          'describe',
+          String.raw`'Subject identifier.\n\nMust be normalized first.'`,
+        ],
       ]);
     });