diff --git a/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/Certificates.json b/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/Certificates.json
index f28c7e76ecc3..70fb39a44396 100644
--- a/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/Certificates.json
+++ b/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/Certificates.json
@@ -304,6 +304,55 @@
           }
         }
       }
+    },
+    "/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Web/certificates/{name}/hostNameBindings": {
+      "get": {
+        "tags": [
+          "Certificates"
+        ],
+        "summary": "Gets all hostname bindings a certificate is used in.",
+        "operationId": "Certificates_ListHostnameBindings",
+        "parameters": [
+          {
+            "$ref": "#/parameters/resourceGroupNameParameter"
+          },
+          {
+            "name": "name",
+            "in": "path",
+            "description": "Name of the certificate.",
+            "required": true,
+            "type": "string"
+          },
+          {
+            "$ref": "#/parameters/subscriptionIdParameter"
+          },
+          {
+            "$ref": "#/parameters/apiVersionParameter"
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "schema": {
+              "$ref": "./CommonDefinitions.json#/definitions/HostNameBindingCollection"
+            }
+          },
+          "default": {
+            "description": "App Service error response.",
+            "schema": {
+              "$ref": "./CommonDefinitions.json#/definitions/DefaultErrorResponse"
+            }
+          }
+        },
+        "x-ms-examples": {
+          "List hostname bindings using certificate": {
+            "$ref": "./examples/ListHostnameBindingsOfCertificate.json"
+          }
+        },
+        "x-ms-pageable": {
+          "nextLinkName": "nextLink"
+        }
+      }
     }
   },
   "definitions": {
diff --git a/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/CommonDefinitions.json b/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/CommonDefinitions.json
index 3b89173e97a9..b05b5df3e737 100644
--- a/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/CommonDefinitions.json
+++ b/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/CommonDefinitions.json
@@ -1183,6 +1183,147 @@
         }
       }
     },
+    "HostNameBinding": {
+      "description": "A hostname binding object.",
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/ProxyOnlyResource"
+        }
+      ],
+      "properties": {
+        "properties": {
+          "description": "HostNameBinding resource specific properties",
+          "type": "object",
+          "properties": {
+            "siteName": {
+              "description": "App Service app name.",
+              "type": "string",
+              "x-ms-mutability": [
+                "create",
+                "read"
+              ]
+            },
+            "domainId": {
+              "description": "Fully qualified ARM domain resource URI.",
+              "type": "string",
+              "x-ms-mutability": [
+                "create",
+                "read"
+              ]
+            },
+            "azureResourceName": {
+              "description": "Azure resource name.",
+              "type": "string",
+              "x-ms-mutability": [
+                "create",
+                "read"
+              ]
+            },
+            "azureResourceType": {
+              "description": "Azure resource type.",
+              "enum": [
+                "Website",
+                "TrafficManager"
+              ],
+              "type": "string",
+              "x-ms-enum": {
+                "name": "AzureResourceType",
+                "modelAsString": false
+              },
+              "x-ms-mutability": [
+                "create",
+                "read"
+              ]
+            },
+            "customHostNameDnsRecordType": {
+              "description": "Custom DNS record type.",
+              "enum": [
+                "CName",
+                "A"
+              ],
+              "type": "string",
+              "x-ms-enum": {
+                "name": "CustomHostNameDnsRecordType",
+                "modelAsString": false
+              },
+              "x-ms-mutability": [
+                "create",
+                "read"
+              ]
+            },
+            "hostNameType": {
+              "description": "Hostname type.",
+              "enum": [
+                "Verified",
+                "Managed"
+              ],
+              "type": "string",
+              "x-ms-enum": {
+                "name": "HostNameType",
+                "modelAsString": false
+              },
+              "x-ms-mutability": [
+                "create",
+                "read"
+              ]
+            },
+            "sslState": {
+              "description": "SSL type",
+              "enum": [
+                "Disabled",
+                "SniEnabled",
+                "IpBasedEnabled"
+              ],
+              "type": "string",
+              "x-ms-enum": {
+                "name": "SslState",
+                "modelAsString": false
+              },
+              "x-ms-mutability": [
+                "create",
+                "read"
+              ]
+            },
+            "thumbprint": {
+              "description": "SSL certificate thumbprint",
+              "type": "string",
+              "x-ms-mutability": [
+                "create",
+                "read"
+              ]
+            },
+            "virtualIP": {
+              "description": "Virtual IP address assigned to the hostname if IP based SSL is enabled.",
+              "type": "string",
+              "readOnly": true
+            }
+          },
+          "x-ms-client-flatten": true
+        }
+      }
+    },
+    "HostNameBindingCollection": {
+      "description": "Collection of hostname bindings.",
+      "required": [
+        "value"
+      ],
+      "type": "object",
+      "properties": {
+        "value": {
+          "description": "Collection of resources.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/HostNameBinding"
+          }
+        },
+        "nextLink": {
+          "description": "Link to next page of resources.",
+          "type": "string",
+          "readOnly": true
+        }
+      }
+    },
     "HostNameSslState": {
       "description": "SSL-enabled hostname.",
       "type": "object",
diff --git a/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/examples/ListHostnameBindingsOfCertificate.json b/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/examples/ListHostnameBindingsOfCertificate.json
new file mode 100644
index 000000000000..eec7cc024560
--- /dev/null
+++ b/specification/web/resource-manager/Microsoft.Web/stable/2021-03-01/examples/ListHostnameBindingsOfCertificate.json
@@ -0,0 +1,45 @@
+{
+  "parameters": {
+    "subscriptionId": "00000000-0000-0000-0000-000000000000",
+    "resourceGroupName": "contosoRG",
+    "name": "contosoCertificate",
+    "api-version": "2021-03-01"
+  },
+  "responses": {
+    "200": {
+      "headers": {},
+      "body": {
+        "value": [
+          {
+            "name": "example.com",
+            "properties": {
+              "siteName": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/contosoRG/providers/Microsoft.Web/sites/contosoSite1",
+              "domainId": null,
+              "sslState": "SniEnabled",
+              "thumbprint": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
+            }
+          },
+          {
+            "name": "www.example.com",
+            "properties": {
+              "siteName": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/contosoRG/providers/Microsoft.Web/sites/contosoSite2",
+              "domainId": null,
+              "sslState": "IpBasedEnabled",
+              "thumbprint": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
+            }
+          },
+          {
+            "name": "test.example.com",
+            "properties": {
+              "siteName": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/contosoRG/providers/Microsoft.Web/sites/contosoSite3",
+              "domainId": null,
+              "sslState": "SniEnabled",
+              "thumbprint": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
+            }
+          }
+        ],
+        "nextLink": null
+      }
+    }
+  }
+}