diff --git a/specification/guestconfiguration/resource-manager/Microsoft.GuestConfiguration/stable/2022-01-25/examples/createOrUpdateGuestConfigurationVMSSAssignment.json b/specification/guestconfiguration/resource-manager/Microsoft.GuestConfiguration/stable/2022-01-25/examples/createOrUpdateGuestConfigurationVMSSAssignment.json
new file mode 100644
index 000000000000..e82e16f13185
--- /dev/null
+++ b/specification/guestconfiguration/resource-manager/Microsoft.GuestConfiguration/stable/2022-01-25/examples/createOrUpdateGuestConfigurationVMSSAssignment.json
@@ -0,0 +1,97 @@
+{
+  "parameters": {
+    "subscriptionId": "mySubscriptionId",
+    "resourceGroupName": "myResourceGroupName",
+    "vmssName": "myVMSSName",
+    "name": "NotInstalledApplicationForWindows",
+    "api-version": "2022-01-25",
+    "parameters": {
+      "location": "westcentralus",
+      "name": "NotInstalledApplicationForWindows",
+      "properties": {
+        "context": "Azure policy",
+        "guestConfiguration": {
+          "name": "NotInstalledApplicationForWindows",
+          "version": "1.*",
+          "contentUri": "https://thisisfake/pacakge",
+          "contentHash": "123contenthash",
+          "assignmentType": "ApplyAndAutoCorrect",
+          "configurationParameter": [
+            {
+              "name": "[InstalledApplication]NotInstalledApplicationResource1;Name",
+              "value": "NotePad,sql"
+            }
+          ]
+        }
+      }
+    }
+  },
+  "responses": {
+    "201": {
+      "headers": {},
+      "body": {
+        "location": "westcentralus",
+        "id": "/subscriptions/mysubscriptionid/resourceGroups/myResourceGroupName/providers/Microsoft.Compute/virtualmachinescalesets/myvmssname/providers/Microsoft.GuestConfiguration/guestConfigurationAssignments/NotInstalledApplicationForWindows",
+        "name": "NotInstalledApplicationForWindows",
+        "properties": {
+          "complianceStatus": "Pending",
+          "assignmentHash": null,
+          "latestReportId": null,
+          "lastComplianceStatusChecked": null,
+          "context": "Azure policy",
+          "resourceType": null,
+          "vmssVMList": null,
+          "guestConfiguration": {
+            "kind": null,
+            "name": "NotInstalledApplicationForWindows",
+            "version": "1.0.0.3",
+            "contentUri": null,
+            "contentHash": null,
+            "contentType": null,
+            "assignmentSource": "AzurePolicy",
+            "configurationParameter": [
+              {
+                "name": "[InstalledApplication]NotInstalledApplicationResource1;Name",
+                "value": "NotePad,sql"
+              }
+            ]
+          },
+          "provisioningState": "Succeeded"
+        }
+      }
+    },
+    "200": {
+      "headers": {},
+      "body": {
+        "location": "westcentralus",
+        "id": "/subscriptions/mysubscriptionid/resourceGroups/myResourceGroupName/providers/Microsoft.Compute/virtualmachinescalesets/myvmssname/providers/Microsoft.GuestConfiguration/guestConfigurationAssignments/NotInstalledApplicationForWindows",
+        "name": "NotInstalledApplicationForWindows",
+        "properties": {
+          "complianceStatus": "Pending",
+          "assignmentHash": null,
+          "latestReportId": null,
+          "lastComplianceStatusChecked": null,
+          "context": "Azure policy",
+          "resourceType": null,
+          "vmssVMList": null,
+          "guestConfiguration": {
+            "kind": null,
+            "name": "NotInstalledApplicationForWindows",
+            "version": "1.0.0.3",
+            "contentUri": null,
+            "contentHash": null,
+            "contentType": null,
+            "assignmentSource": "AzurePolicy",
+            "configurationParameter": [
+              {
+                "name": "[InstalledApplication]NotInstalledApplicationResource1;Name",
+                "value": "NotePad,sql"
+              }
+            ]
+          },
+          "provisioningState": "Succeeded"
+        }
+      }
+    }
+  }
+}
diff --git a/specification/guestconfiguration/resource-manager/Microsoft.GuestConfiguration/stable/2022-01-25/guestconfiguration.json b/specification/guestconfiguration/resource-manager/Microsoft.GuestConfiguration/stable/2022-01-25/guestconfiguration.json
index 405fdc48945a..a3dc6dbf28d9 100644
--- a/specification/guestconfiguration/resource-manager/Microsoft.GuestConfiguration/stable/2022-01-25/guestconfiguration.json
+++ b/specification/guestconfiguration/resource-manager/Microsoft.GuestConfiguration/stable/2022-01-25/guestconfiguration.json
@@ -809,6 +809,74 @@
       }
     },
     "/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/virtualMachineScaleSets/{vmssName}/providers/Microsoft.GuestConfiguration/guestConfigurationAssignments/{name}": {
+      "put": {
+        "tags": [
+          "GuestConfigurationAssignments"
+        ],
+        "operationId": "GuestConfigurationAssignmentsVMSS_CreateOrUpdate",
+        "description": "Creates an association between a VMSS and guest configuration",
+        "x-ms-examples": {
+          "Create or update guest configuration assignment": {
+            "$ref": "./examples/createOrUpdateGuestConfigurationVMSSAssignment.json"
+          }
+        },
+        "parameters": [
+          {
+            "$ref": "../../common/v1/definitions.json#/parameters/SubscriptionIdParameter"
+          },
+          {
+            "$ref": "../../common/v1/definitions.json#/parameters/ResourceGroupNameParameter"
+          },
+          {
+            "$ref": "../../common/v1/definitions.json#/parameters/VMSSNameParameter"
+          },
+          {
+            "name": "name",
+            "in": "path",
+            "required": true,
+            "type": "string",
+            "description": "Name of the guest configuration assignment."
+          },
+          {
+            "name": "parameters",
+            "in": "body",
+            "required": true,
+            "schema": {
+              "$ref": "#/definitions/GuestConfigurationAssignment"
+            },
+            "description": "Parameters supplied to the create or update guest configuration assignment."
+          },
+          {
+            "$ref": "../../common/v1/definitions.json#/parameters/ApiVersionParameter"
+          }
+        ],
+        "responses": {
+          "201": {
+            "description": "Created. The guest configuration assignment for the VMSS was created successfully.",
+            "schema": {
+              "$ref": "#/definitions/GuestConfigurationAssignment"
+            }
+          },
+          "200": {
+            "description": "OK. The guest configuration assignment for the VMSS was updated successfully.",
+            "schema": {
+              "$ref": "#/definitions/GuestConfigurationAssignment"
+            }
+          },
+          "default": {
+            "description": "Error response describing why the operation failed.",
+            "schema": {
+              "$ref": "../../common/v1/definitions.json#/definitions/ErrorResponse"
+            }
+          }
+        },
+        "produces": [
+          "application/json"
+        ],
+        "consumes": [
+          "application/json"
+        ]
+      },
       "get": {
         "tags": [
           "GuestConfigurationAssignments"