diff --git a/common.go b/common.go
index 62324de..007f0f4 100644
--- a/common.go
+++ b/common.go
@@ -1493,3 +1493,18 @@ func isSupportedSignatureAlgorithm(sigAlg SignatureScheme, supportedSignatureAlg
 	}
 	return false
 }
+
+// CertificateVerificationError is returned when certificate verification fails during the handshake.
+type CertificateVerificationError struct {
+	// UnverifiedCertificates and its contents should not be modified.
+	UnverifiedCertificates []*x509.Certificate
+	Err                    error
+}
+
+func (e *CertificateVerificationError) Error() string {
+	return fmt.Sprintf("tls: failed to verify certificate: %s", e.Err)
+}
+
+func (e *CertificateVerificationError) Unwrap() error {
+	return e.Err
+}
diff --git a/handshake_client.go b/handshake_client.go
index 2e3b693..7cf906c 100644
--- a/handshake_client.go
+++ b/handshake_client.go
@@ -876,7 +876,7 @@ func (c *Conn) verifyServerCertificate(certificates [][]byte) error {
 		c.verifiedChains, err = certs[0].Verify(opts)
 		if err != nil {
 			c.sendAlert(alertBadCertificate)
-			return err
+			return &CertificateVerificationError{UnverifiedCertificates: certs, Err: err}
 		}
 	}
 
diff --git a/handshake_server.go b/handshake_server.go
index fc0a7ac..682cfc2 100644
--- a/handshake_server.go
+++ b/handshake_server.go
@@ -831,7 +831,7 @@ func (c *Conn) processCertsFromClient(certificate Certificate) error {
 		chains, err := certs[0].Verify(opts)
 		if err != nil {
 			c.sendAlert(alertBadCertificate)
-			return errors.New("tls: failed to verify client certificate: " + err.Error())
+			return &CertificateVerificationError{UnverifiedCertificates: certs, Err: err}
 		}
 
 		c.verifiedChains = chains