diff --git a/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/datafactory.json b/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/datafactory.json
index 08948064bf58..7dc0876d7aa8 100644
--- a/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/datafactory.json
+++ b/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/datafactory.json
@@ -3101,6 +3101,39 @@
         "message"
       ]
     },
+    "VariableDefinitionSpecification": {
+      "description": "Definition of variable for a Pipeline.",
+      "type": "object",
+      "additionalProperties": {
+        "$ref": "#/definitions/VariableSpecification"
+      }
+    },
+    "VariableSpecification": {
+      "description": "Definition of a single variable for a Pipeline.",
+      "type": "object",
+      "properties": {
+        "type": {
+          "type": "string",
+          "description": "Variable type.",
+          "enum": [
+            "String",
+            "Bool",
+            "Array"
+          ],
+          "x-ms-enum": {
+            "name": "VariableType",
+            "modelAsString": true
+          }
+        },
+        "defaultValue": {
+          "type": "object",
+          "description": "Default value of variable."
+        }
+      },
+      "required": [
+        "type"
+      ]
+    },
     "ParameterDefinitionSpecification": {
       "description": "Definition of all parameters for an entity.",
       "type": "object",
diff --git a/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/entityTypes/Pipeline.json b/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/entityTypes/Pipeline.json
index a430e5c0846e..24fdecaf29ea 100644
--- a/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/entityTypes/Pipeline.json
+++ b/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/entityTypes/Pipeline.json
@@ -25,6 +25,10 @@
           "$ref": "../datafactory.json#/definitions/ParameterDefinitionSpecification",
           "description": "List of parameters for pipeline."
         },
+        "variables": {
+          "$ref": "../datafactory.json#/definitions/VariableDefinitionSpecification",
+          "description": "List of variables for pipeline."
+        },
         "concurrency": {
           "type": "integer",
           "minimum": 1,
@@ -3023,6 +3027,70 @@
       "required": [
         "pythonFile"
       ]
+    },
+    "SetVariableActivity": {
+      "x-ms-discriminator-value": "SetVariable",
+      "description": "Set value for a Variable.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/ControlActivity"
+        }
+      ],
+      "properties": {
+        "typeProperties": {
+          "description": "Set Variable activity properties.",
+          "x-ms-client-flatten": true,
+          "$ref": "#/definitions/SetVariableActivityTypeProperties"
+        }
+      },
+      "required": [
+        "typeProperties"
+      ]
+    },
+    "SetVariableActivityTypeProperties": {
+      "description": "SetVariable activity properties.",
+      "properties": {
+        "variableName": {
+          "description": "Name of the variable whose value needs to be set.",
+          "type": "string"
+        },
+        "value": {
+          "description": "Value to be set. Could be a static value or Expression",
+          "type": "object"
+        }
+      }
+    },
+    "AppendVariableActivity": {
+      "x-ms-discriminator-value": "AppendVariable",
+      "description": "Append value for a Variable of type Array.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/ControlActivity"
+        }
+      ],
+      "properties": {
+        "typeProperties": {
+          "description": "Append Variable activity properties.",
+          "x-ms-client-flatten": true,
+          "$ref": "#/definitions/AppendVariableActivityTypeProperties"
+        }
+      },
+      "required": [
+        "typeProperties"
+      ]
+    },
+    "AppendVariableActivityTypeProperties": {
+      "description": "AppendVariable activity properties.",
+      "properties": {
+        "variableName": {
+          "description": "Name of the variable whose value needs to be appended to.",
+          "type": "string"
+        },
+        "value": {
+          "description": "Value to be appended. Could be a static value or Expression",
+          "type": "object"
+        }
+      }
     }
   }
 }
diff --git a/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/examples/Pipelines_Create.json b/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/examples/Pipelines_Create.json
index 36720c98f369..a35819f0b35c 100644
--- a/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/examples/Pipelines_Create.json
+++ b/specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/examples/Pipelines_Create.json
@@ -62,6 +62,11 @@
           "OutputBlobNameList": {
             "type": "Array"
           }
+        },
+        "variables": {
+          "TestVariableArray": {
+            "type": "Array"
+          }
         }
       }
     },
@@ -136,6 +141,11 @@
             "OutputBlobNameList": {
               "type": "Array"
             }
+          },
+          "variables": {
+            "TestVariableArray": {
+              "type": "Array"
+            }
           }
         },
         "etag": "0a0069d4-0000-0000-0000-5b245bd50000"