diff --git a/src/core/config/OperationConfig.json b/src/core/config/OperationConfig.json
index 024e5952..fee0ec09 100644
--- a/src/core/config/OperationConfig.json
+++ b/src/core/config/OperationConfig.json
@@ -210,6 +210,25 @@
             }
         ]
     },
+    "Set Difference": {
+        "module": "Default",
+        "description": "Get the Difference of two sets",
+        "inputType": "string",
+        "outputType": "string",
+        "flowControl": false,
+        "args": [
+            {
+                "name": "Sample delimiter",
+                "type": "binaryString",
+                "value": "\\n\\n"
+            },
+            {
+                "name": "Item delimiter",
+                "type": "binaryString",
+                "value": ","
+            }
+        ]
+    },
     "Set Intersection": {
         "module": "Default",
         "description": "Get the intersection of two sets",
diff --git a/src/core/config/modules/Default.mjs b/src/core/config/modules/Default.mjs
index 28528882..8a1496fa 100644
--- a/src/core/config/modules/Default.mjs
+++ b/src/core/config/modules/Default.mjs
@@ -9,6 +9,7 @@ import FromBase32 from "../../operations/FromBase32";
 import FromBase64 from "../../operations/FromBase64";
 import FromHex from "../../operations/FromHex";
 import RawDeflate from "../../operations/RawDeflate";
+import SetDifference from "../../operations/SetDifference";
 import SetIntersection from "../../operations/SetIntersection";
 import SetOps from "../../operations/SetOps";
 import SetUnion from "../../operations/SetUnion";
@@ -24,6 +25,7 @@ OpModules.Default = {
     "From Base64": FromBase64,
     "From Hex": FromHex,
     "Raw Deflate": RawDeflate,
+    "Set Difference": SetDifference,
     "Set Intersection": SetIntersection,
     "": SetOps,
     "Set Union": SetUnion,
diff --git a/src/core/operations/SetDifference.mjs b/src/core/operations/SetDifference.mjs
new file mode 100644
index 00000000..6b2d076f
--- /dev/null
+++ b/src/core/operations/SetDifference.mjs
@@ -0,0 +1,86 @@
+/**
+ * @author d98762625 [d98762625@gmail.com]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
+import Utils from "../Utils";
+import Operation from "../Operation";
+
+/**
+ * Set Difference operation
+ */
+class SetDifference extends Operation {
+
+    /**
+     * Set Difference constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Set Difference";
+        this.module = "Default";
+        this.description = "Get the Difference of two sets";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [
+            {
+                name: "Sample delimiter",
+                type: "binaryString",
+                value: Utils.escapeHtml("\\n\\n")
+            },
+            {
+                name: "Item delimiter",
+                type: "binaryString",
+                value: ","
+            },
+        ];
+    }
+
+    /**
+     * Validate input length
+     * @param {Object[]} sets
+     * @throws {Error} if not two sets
+     */
+    validateSampleNumbers(sets) {
+        if (!sets || (sets.length !== 2)) {
+            throw "Incorrect number of sets, perhaps you need to modify the sample delimiter or add more samples?";
+        }
+    }
+
+    /**
+     * Run the difference operation
+     * @param input
+     * @param args
+     */
+    run(input, args) {
+        [this.sampleDelim, this.itemDelimiter] = args;
+        const sets = input.split(this.sampleDelim);
+
+        try {
+            this.validateSampleNumbers(sets);
+        } catch (e) {
+            return e;
+        }
+
+        return Utils.escapeHtml(this.runSetDifferencez(...sets.map(s => s.split(this.itemDelimiter))));
+    }
+
+    /**
+     * Get elements in set a that are not in set b
+     *
+     * @param {Object[]} a
+     * @param {Object[]} b
+     * @returns {Object[]}
+     */
+    runSetDifference(a, b) {
+        return a
+            .filter((item) => {
+                return b.indexOf(item) === -1;
+            })
+            .join(this.itemDelimiter);
+    }
+
+}
+
+export default SetDifference;
diff --git a/src/core/operations/SetUnion.mjs b/src/core/operations/SetUnion.mjs
index bde0cae7..bfe39d11 100644
--- a/src/core/operations/SetUnion.mjs
+++ b/src/core/operations/SetUnion.mjs
@@ -1,3 +1,9 @@
+/**
+ * @author d98762625 [d98762625@gmail.com]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
 import Utils from "../Utils";
 import Operation from "../Operation";
 
diff --git a/src/core/operations/index.mjs b/src/core/operations/index.mjs
index ae6c12df..fce3dd9b 100644
--- a/src/core/operations/index.mjs
+++ b/src/core/operations/index.mjs
@@ -12,6 +12,7 @@ import Gunzip from "./Gunzip";
 import Gzip from "./Gzip";
 import RawDeflate from "./RawDeflate";
 import RawInflate from "./RawInflate";
+import SetDifference from "./SetDifference";
 import SetIntersection from "./SetIntersection";
 import SetOps from "./SetOps";
 import SetUnion from "./SetUnion";
@@ -32,6 +33,7 @@ export {
     Gzip,
     RawDeflate,
     RawInflate,
+    SetDifference,
     SetIntersection,
     SetOps,
     SetUnion,
diff --git a/test/index.mjs b/test/index.mjs
index 73638537..fdcd3102 100644
--- a/test/index.mjs
+++ b/test/index.mjs
@@ -49,8 +49,7 @@ import "./tests/operations/Base64";
 // import "./tests/operations/SeqUtils.js";
 import "./tests/operations/SetUnion";
 import "./tests/operations/SetIntersection";
-
-
+import "./tests/operations/SetDifference";
 
 let allTestsPassing = true;
 const testStatusCounts = {
diff --git a/test/tests/operations/SetDifference.mjs b/test/tests/operations/SetDifference.mjs
new file mode 100644
index 00000000..3bc91d3f
--- /dev/null
+++ b/test/tests/operations/SetDifference.mjs
@@ -0,0 +1,56 @@
+/**
+ * Set Difference tests.
+ *
+ * @author d98762625
+ *
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+import TestRegister from "../../TestRegister";
+
+TestRegister.addTests([
+    {
+        name: "Set Difference",
+        input: "1 2 3 4 5\n\n3 4 5 6 7",
+        expectedOutput: "1 2",
+        recipeConfig: [
+            {
+                op: "Set Difference",
+                args: ["\n\n", " "],
+            },
+        ],
+    },
+    {
+        name: "Set Difference: wrong sample count",
+        input: "1 2 3 4 5_3_4 5 6 7",
+        expectedOutput: "Incorrect number of sets, perhaps you need to modify the sample delimiter or add more samples?",
+        recipeConfig: [
+            {
+                op: "Set Difference",
+                args: [" ", "_"],
+            },
+        ],
+    },
+    {
+        name: "Set Difference: item delimiter",
+        input: "1;2;3;4;5\n\n3;4;5;6;7",
+        expectedOutput: "1;2",
+        recipeConfig: [
+            {
+                op: "Set Difference",
+                args: ["\n\n", ";"],
+            },
+        ],
+    },
+    {
+        name: "Set Difference: sample delimiter",
+        input: "1;2;3;4;5===3;4;5;6;7",
+        expectedOutput: "1;2",
+        recipeConfig: [
+            {
+                op: "Set Difference",
+                args: ["===", ";"],
+            },
+        ],
+    },
+]);
diff --git a/test/tests/operations/SetIntersection.mjs b/test/tests/operations/SetIntersection.mjs
index b6121893..83809b6e 100644
--- a/test/tests/operations/SetIntersection.mjs
+++ b/test/tests/operations/SetIntersection.mjs
@@ -1,9 +1,9 @@
 /**
- * Set Operations tests.
+ * Set Intersection tests.
  *
  * @author d98762625
  *
- * @copyright Crown Copyright 2017
+ * @copyright Crown Copyright 2018
  * @license Apache-2.0
  */
 import TestRegister from "../../TestRegister";
diff --git a/test/tests/operations/SetUnion.mjs b/test/tests/operations/SetUnion.mjs
index f214549a..a78bdc36 100644
--- a/test/tests/operations/SetUnion.mjs
+++ b/test/tests/operations/SetUnion.mjs
@@ -1,9 +1,9 @@
 /**
- * Set Operations tests.
+ * Set Union tests.
  *
  * @author d98762625
  *
- * @copyright Crown Copyright 2017
+ * @copyright Crown Copyright 2018
  * @license Apache-2.0
  */
 import TestRegister from "../../TestRegister";