diff --git a/src/sonic-yang-models/tests/files/sample_config_db.json b/src/sonic-yang-models/tests/files/sample_config_db.json
index 483142bbb93b..0d2827ae48ae 100644
--- a/src/sonic-yang-models/tests/files/sample_config_db.json
+++ b/src/sonic-yang-models/tests/files/sample_config_db.json
@@ -869,7 +869,7 @@
                 "alias": "Eth31/1",
                 "lanes": "121,122",
                 "description": "",
-                "fec": "fc",
+                "fec": "auto",
                 "speed": "11100",
                 "tpid": "0x8100",
                 "admin_status": "up"
diff --git a/src/sonic-yang-models/tests/yang_model_tests/tests/port.json b/src/sonic-yang-models/tests/yang_model_tests/tests/port.json
index cbcd1def5b25..cffa5bac65f7 100644
--- a/src/sonic-yang-models/tests/yang_model_tests/tests/port.json
+++ b/src/sonic-yang-models/tests/yang_model_tests/tests/port.json
@@ -128,5 +128,8 @@
          "desc": "Out of range subport number",
          "eStrKey": "Range",
          "eStr": "0..8"
+     },
+     "PORT_AUTO_FEC_TEST": {
+         "desc": "PORT_AUTO_FEC_TEST validate auto mode in fec."
      }
 }
diff --git a/src/sonic-yang-models/tests/yang_model_tests/tests_config/port.json b/src/sonic-yang-models/tests/yang_model_tests/tests_config/port.json
index b557e183e95a..5879bbac55a3 100644
--- a/src/sonic-yang-models/tests/yang_model_tests/tests_config/port.json
+++ b/src/sonic-yang-models/tests/yang_model_tests/tests_config/port.json
@@ -638,5 +638,24 @@
                 ]
             }
         }
+    },
+
+    "PORT_AUTO_FEC_TEST": {
+        "sonic-port:sonic-port": {
+            "sonic-port:PORT": {
+                "PORT_LIST": [
+                    {
+                        "admin_status": "up",
+                        "alias": "eth8",
+                        "description": "Ethernet8",
+                        "fec": "auto",
+                        "lanes": "65",
+                        "mtu": 9000,
+                        "name": "Ethernet8",
+                        "speed": 25000
+                    }
+                ]
+            }
+        }
     }
 }
diff --git a/src/sonic-yang-models/yang-models/sonic-port.yang b/src/sonic-yang-models/yang-models/sonic-port.yang
index f5b5a936ab94..f164140d0d81 100644
--- a/src/sonic-yang-models/yang-models/sonic-port.yang
+++ b/src/sonic-yang-models/yang-models/sonic-port.yang
@@ -151,7 +151,7 @@ module sonic-port{
 
 				leaf fec {
 					type string {
-						pattern "rs|fc|none";
+						pattern "rs|fc|none|auto";
 					}
 				}