diff --git a/deno/lib/__tests__/string.test.ts b/deno/lib/__tests__/string.test.ts
index 2a25f650e..7798db244 100644
--- a/deno/lib/__tests__/string.test.ts
+++ b/deno/lib/__tests__/string.test.ts
@@ -266,6 +266,8 @@ test("ulid", () => {
   ulid.parse("01ARZ3NDEKTSV4RRFFQ69G5FAV");
   const result = ulid.safeParse("invalidulid");
   expect(result.success).toEqual(false);
+  const tooLong = "01ARZ3NDEKTSV4RRFFQ69G5FAVA"
+  expect(ulid.safeParse(tooLong).success).toEqual(false);
   if (!result.success) {
     expect(result.error.issues[0].message).toEqual("Invalid ulid");
   }
diff --git a/deno/lib/types.ts b/deno/lib/types.ts
index 0ddeb15da..80939da3b 100644
--- a/deno/lib/types.ts
+++ b/deno/lib/types.ts
@@ -547,7 +547,7 @@ export interface ZodStringDef extends ZodTypeDef {
 
 const cuidRegex = /^c[^\s-]{8,}$/i;
 const cuid2Regex = /^[a-z][a-z0-9]*$/;
-const ulidRegex = /[0-9A-HJKMNP-TV-Z]{26}/;
+const ulidRegex = /^[0-9A-HJKMNP-TV-Z]{26}$/;
 // const uuidRegex =
 //   /^([a-f0-9]{8}-[a-f0-9]{4}-[1-5][a-f0-9]{3}-[a-f0-9]{4}-[a-f0-9]{12}|00000000-0000-0000-0000-000000000000)$/i;
 const uuidRegex =
diff --git a/src/__tests__/string.test.ts b/src/__tests__/string.test.ts
index b870ad1b6..c1393c0fd 100644
--- a/src/__tests__/string.test.ts
+++ b/src/__tests__/string.test.ts
@@ -265,6 +265,8 @@ test("ulid", () => {
   ulid.parse("01ARZ3NDEKTSV4RRFFQ69G5FAV");
   const result = ulid.safeParse("invalidulid");
   expect(result.success).toEqual(false);
+  const tooLong = "01ARZ3NDEKTSV4RRFFQ69G5FAVA"
+  expect(ulid.safeParse(tooLong).success).toEqual(false);
   if (!result.success) {
     expect(result.error.issues[0].message).toEqual("Invalid ulid");
   }
diff --git a/src/types.ts b/src/types.ts
index 924fa3fba..20bb60dae 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -547,7 +547,7 @@ export interface ZodStringDef extends ZodTypeDef {
 
 const cuidRegex = /^c[^\s-]{8,}$/i;
 const cuid2Regex = /^[a-z][a-z0-9]*$/;
-const ulidRegex = /[0-9A-HJKMNP-TV-Z]{26}/;
+const ulidRegex = /^[0-9A-HJKMNP-TV-Z]{26}$/;
 // const uuidRegex =
 //   /^([a-f0-9]{8}-[a-f0-9]{4}-[1-5][a-f0-9]{3}-[a-f0-9]{4}-[a-f0-9]{12}|00000000-0000-0000-0000-000000000000)$/i;
 const uuidRegex =