diff --git a/lib/std/crypto/tls.zig b/lib/std/crypto/tls.zig
index 252defcb2d5dcc955fb4b102146b16ecf380b48e..2f9099c28f543baa19990eb1d2276d4f335e3f20 100644
--- a/lib/std/crypto/tls.zig
+++ b/lib/std/crypto/tls.zig
@@ -133,6 +133,8 @@ pub const ExtensionType = enum(u16) {
     signature_algorithms_cert = 50,
     /// RFC 8446
     key_share = 51,
+    /// RFC 9000
+    quic_transport_parameters = 57,
 
     _,
 };