diff --git a/include/zephyr/net/tls_credentials.h b/include/zephyr/net/tls_credentials.h
index 1002eee7e64..d4bce6cd6fe 100644
--- a/include/zephyr/net/tls_credentials.h
+++ b/include/zephyr/net/tls_credentials.h
@@ -77,6 +77,8 @@ enum tls_credential_type {
  */
 typedef int sec_tag_t;
 
+#define SEC_TAG_TLS_INVALID (-1) /**< Invalid secure tag value. */
+
 /**
  * @brief Add a TLS credential.
  *