diff --git a/ark/type/__tests__/keywords/uuid.test.ts b/ark/type/__tests__/keywords/uuid.test.ts
index 3bd966dd5..0c0ec9864 100644
--- a/ark/type/__tests__/keywords/uuid.test.ts
+++ b/ark/type/__tests__/keywords/uuid.test.ts
@@ -25,6 +25,23 @@ contextualize(() => {
 		)
 	})
 
+	it("JSON Schema pattern accepts uppercase like the runtime check", () => {
+		const upper = validUuidV4.toUpperCase()
+
+		const Uuid = type("string.uuid")
+		attest(Uuid(upper)).equals(upper)
+		const uuidSchema = Uuid.toJsonSchema() as {
+			anyOf: { pattern?: string }[]
+		}
+		const versionedPattern = uuidSchema.anyOf[0].pattern!
+		attest(new RegExp(versionedPattern, "u").test(upper)).equals(true)
+
+		const Uuidv4 = type("string.uuid.v4")
+		attest(Uuidv4(upper)).equals(upper)
+		const v4Pattern = (Uuidv4.toJsonSchema() as { pattern: string }).pattern
+		attest(new RegExp(v4Pattern, "u").test(upper)).equals(true)
+	})
+
 	it("rejects partial matches", () => {
 		const Uuid = type("string.uuid")
 		attest(Uuid("dbb1e8e0-40fc-4c14-87eb-61b25d166a1b extra").toString()).snap(
diff --git a/ark/type/keywords/string.ts b/ark/type/keywords/string.ts
index 0779d70a5..2b76509c3 100644
--- a/ark/type/keywords/string.ts
+++ b/ark/type/keywords/string.ts
@@ -841,37 +841,37 @@ export const uuid = Scope.module(
 		"#nil": "'00000000-0000-0000-0000-000000000000'",
 		"#max": "'ffffffff-ffff-ffff-ffff-ffffffffffff'",
 		"#versioned":
-			/^[\da-f]{8}-[\da-f]{4}-[1-8][\da-f]{3}-[89ab][\da-f]{3}-[\da-f]{12}$/i,
+			/^[\dA-Fa-f]{8}-[\dA-Fa-f]{4}-[1-8][\dA-Fa-f]{3}-[89ABab][\dA-Fa-f]{3}-[\dA-Fa-f]{12}$/,
 		v1: regexStringNode(
-			/^[\da-f]{8}-[\da-f]{4}-1[\da-f]{3}-[89ab][\da-f]{3}-[\da-f]{12}$/i,
+			/^[\dA-Fa-f]{8}-[\dA-Fa-f]{4}-1[\dA-Fa-f]{3}-[89ABab][\dA-Fa-f]{3}-[\dA-Fa-f]{12}$/,
 			"a UUIDv1"
 		),
 		v2: regexStringNode(
-			/^[\da-f]{8}-[\da-f]{4}-2[\da-f]{3}-[89ab][\da-f]{3}-[\da-f]{12}$/i,
+			/^[\dA-Fa-f]{8}-[\dA-Fa-f]{4}-2[\dA-Fa-f]{3}-[89ABab][\dA-Fa-f]{3}-[\dA-Fa-f]{12}$/,
 			"a UUIDv2"
 		),
 		v3: regexStringNode(
-			/^[\da-f]{8}-[\da-f]{4}-3[\da-f]{3}-[89ab][\da-f]{3}-[\da-f]{12}$/i,
+			/^[\dA-Fa-f]{8}-[\dA-Fa-f]{4}-3[\dA-Fa-f]{3}-[89ABab][\dA-Fa-f]{3}-[\dA-Fa-f]{12}$/,
 			"a UUIDv3"
 		),
 		v4: regexStringNode(
-			/^[\da-f]{8}-[\da-f]{4}-4[\da-f]{3}-[89ab][\da-f]{3}-[\da-f]{12}$/i,
+			/^[\dA-Fa-f]{8}-[\dA-Fa-f]{4}-4[\dA-Fa-f]{3}-[89ABab][\dA-Fa-f]{3}-[\dA-Fa-f]{12}$/,
 			"a UUIDv4"
 		),
 		v5: regexStringNode(
-			/^[\da-f]{8}-[\da-f]{4}-5[\da-f]{3}-[89ab][\da-f]{3}-[\da-f]{12}$/i,
+			/^[\dA-Fa-f]{8}-[\dA-Fa-f]{4}-5[\dA-Fa-f]{3}-[89ABab][\dA-Fa-f]{3}-[\dA-Fa-f]{12}$/,
 			"a UUIDv5"
 		),
 		v6: regexStringNode(
-			/^[\da-f]{8}-[\da-f]{4}-6[\da-f]{3}-[89ab][\da-f]{3}-[\da-f]{12}$/i,
+			/^[\dA-Fa-f]{8}-[\dA-Fa-f]{4}-6[\dA-Fa-f]{3}-[89ABab][\dA-Fa-f]{3}-[\dA-Fa-f]{12}$/,
 			"a UUIDv6"
 		),
 		v7: regexStringNode(
-			/^[\da-f]{8}-[\da-f]{4}-7[\da-f]{3}-[89ab][\da-f]{3}-[\da-f]{12}$/i,
+			/^[\dA-Fa-f]{8}-[\dA-Fa-f]{4}-7[\dA-Fa-f]{3}-[89ABab][\dA-Fa-f]{3}-[\dA-Fa-f]{12}$/,
 			"a UUIDv7"
 		),
 		v8: regexStringNode(
-			/^[\da-f]{8}-[\da-f]{4}-8[\da-f]{3}-[89ab][\da-f]{3}-[\da-f]{12}$/i,
+			/^[\dA-Fa-f]{8}-[\dA-Fa-f]{4}-8[\dA-Fa-f]{3}-[89ABab][\dA-Fa-f]{3}-[\dA-Fa-f]{12}$/,
 			"a UUIDv8"
 		)
 	},