diff --git a/quiche/quic/core/crypto/proof_source.h b/quiche/quic/core/crypto/proof_source.h
index 6391ae2..b66a18b 100644
--- a/quiche/quic/core/crypto/proof_source.h
+++ b/quiche/quic/core/crypto/proof_source.h
@@ -370,6 +370,9 @@
   // Get the TLS ciphersuite negotiated during the handshake, or nullopt if the
   // handshake has not selected one yet.
   virtual std::optional<uint16_t> GetCiphersuite() const = 0;
+
+  // Get the ID of the NamedGroup negotiated during the handshake.
+  virtual uint16_t GetNegotiatedCurve() const = 0;
 };
 
 // ProofSourceHandle is an interface by which a TlsServerHandshaker can obtain
diff --git a/quiche/quic/core/tls_server_handshaker.cc b/quiche/quic/core/tls_server_handshaker.cc
index 3336648..a0fa3c8 100644
--- a/quiche/quic/core/tls_server_handshaker.cc
+++ b/quiche/quic/core/tls_server_handshaker.cc
@@ -1250,6 +1250,10 @@
   return SSL_CIPHER_get_protocol_id(cipher);
 }
 
+uint16_t TlsServerHandshaker::GetNegotiatedCurve() const {
+  return SSL_get_group_id(ssl());
+}
+
 bool TlsServerHandshaker::ValidateHostname(const std::string& hostname) const {
   if (!QuicHostnameUtils::IsValidSNI(hostname)) {
     // TODO(b/151676147): Include this error string in the CONNECTION_CLOSE
diff --git a/quiche/quic/core/tls_server_handshaker.h b/quiche/quic/core/tls_server_handshaker.h
index dccf620..cf36829 100644
--- a/quiche/quic/core/tls_server_handshaker.h
+++ b/quiche/quic/core/tls_server_handshaker.h
@@ -222,6 +222,8 @@
 
   std::optional<uint16_t> GetCiphersuite() const override;
 
+  uint16_t GetNegotiatedCurve() const override;
+
   void SetIgnoreTicketOpen(bool value) { ignore_ticket_open_ = value; }
 
   const SSL_CIPHER* GetCipher() const override {