diff --git a/caddytls/config.go b/caddytls/config.go
index 6632aed..767886c 100644
--- a/caddytls/config.go
+++ b/caddytls/config.go
@@ -372,7 +372,7 @@ func SetDefaultTLSParams(config *Config) {
 		config.ProtocolMinVersion = tls.VersionTLS11
 	}
 	if config.ProtocolMaxVersion == 0 {
-		config.ProtocolMaxVersion = tls.VersionTLS12
+		config.ProtocolMaxVersion = tls.VersionTLS13
 	}
 
 	// Prefer server cipher suites
@@ -394,6 +394,7 @@ var supportedProtocols = map[string]uint16{
 	"tls1.0": tls.VersionTLS10,
 	"tls1.1": tls.VersionTLS11,
 	"tls1.2": tls.VersionTLS12,
+	"tls1.3": tls.VersionTLS13,
 }
 
 // Map of supported ciphers, used only for parsing config.