diff --git a/Jakefile.js b/Jakefile.js
index acc614421e6..474303a9722 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -680,9 +680,9 @@ function cleanTestDirs() {
 }
 
 // used to pass data from jake command line directly to run.js
-function writeTestConfigFile(tests, light, testConfigFile) {
-    console.log('Running test(s): ' + tests);
-    var testConfigContents = JSON.stringify({ test: [tests], light: light });
+function writeTestConfigFile(tests, light, taskConfigsFolder, workerCount, testConfigFile) {
+    var testConfigContents = JSON.stringify({ test: tests ? [tests] : undefined, light: light, workerCount: workerCount, taskConfigsFolder: taskConfigsFolder });
+    console.log('Running tests with config: ' + testConfigContents);
     fs.writeFileSync('test.config', testConfigContents);
 }
 
@@ -692,7 +692,7 @@ function deleteTemporaryProjectOutput() {
     }
 }
 
-function runConsoleTests(defaultReporter, defaultSubsets) {
+function runConsoleTests(defaultReporter, runInParallel) {
     cleanTestDirs();
     var debug = process.env.debug || process.env.d;
     tests = process.env.test || process.env.tests || process.env.t;
@@ -701,9 +701,22 @@ function runConsoleTests(defaultReporter, defaultSubsets) {
     if(fs.existsSync(testConfigFile)) {
         fs.unlinkSync(testConfigFile);
     }
+    var workerCount, taskConfigsFolder;
+    if (runInParallel) {
+        // generate name to store task configuration files
+        var prefix = os.tmpdir() + "/ts-tests";
+        var i = 1;
+        do {
+            taskConfigsFolder = prefix + i;
+            i++;
+        } while (fs.existsSync(taskConfigsFolder));
+        fs.mkdirSync(taskConfigsFolder);
 
-    if (tests || light) {
-        writeTestConfigFile(tests, light, testConfigFile);
+        workerCount = process.env.workerCount || os.cpus().length;
+    }
+
+    if (tests || light || taskConfigsFolder) {
+        writeTestConfigFile(tests, light, taskConfigsFolder, workerCount, testConfigFile);
     }
 
     if (tests && tests.toLocaleLowerCase() === "rwc") {
@@ -717,61 +730,93 @@ function runConsoleTests(defaultReporter, defaultSubsets) {
 
     // timeout normally isn't necessary but Travis-CI has been timing out on compiler baselines occasionally
     // default timeout is 2sec which really should be enough, but maybe we just need a small amount longer
-    var subsetRegexes;
-    if(defaultSubsets.length === 0) {
-        subsetRegexes = [tests];
-    }
-    else {
-        var subsets = tests ? tests.split("|") : defaultSubsets;
-        subsetRegexes = subsets.map(function (sub) { return "^" + sub + ".*$"; });
-        subsetRegexes.push("^(?!" + subsets.join("|") + ").*$");
-    }
-    var counter = subsetRegexes.length;
-    var errorStatus;
-    subsetRegexes.forEach(function (subsetRegex, i) {
-        tests = subsetRegex ? ' -g "' + subsetRegex + '"' : '';
+    if(!runInParallel) {
+        tests = tests ? ' -g "' + tests + '"' : '';
         var cmd = "mocha" + (debug ? " --debug-brk" : "") + " -R " + reporter + tests + colors + ' -t ' + testTimeout + ' ' + run;
         console.log(cmd);
-        function finish(status) {
-            counter--;
-            // save first error status
-            if (status !== undefined && errorStatus === undefined) {
-                errorStatus = status;
-            }
-
-            deleteTemporaryProjectOutput();
-            if (counter !== 0 || errorStatus === undefined) {
-                // run linter when last worker is finished
-                if (lintFlag && counter === 0) {
-                    var lint = jake.Task['lint'];
-                    lint.addListener('complete', function () {
-                        complete();
-                    });
-                    lint.invoke();
-                }
-                complete();
-            }
-            else {
-                fail("Process exited with code " + status);
-            }
-        }
         exec(cmd, function () {
+            runLinter();
             finish();
         }, function(e, status) {
             finish(status);
         });
-    });
+        
+    }
+    else {
+        // run task to load all tests and partition them between workers 
+        var cmd = "mocha " + " -R min " + colors + run;
+        console.log(cmd);
+        exec(cmd, function() {
+            // read all configuration files and spawn a worker for every config
+            var configFiles = fs.readdirSync(taskConfigsFolder);
+            var counter = configFiles.length;
+            var firstErrorStatus;
+            // schedule work for chunks
+            configFiles.forEach(function (f) {
+                var configPath = path.join(taskConfigsFolder, f);
+                var workerCmd = "mocha" + " -t " + testTimeout + " -R " + reporter + " " + colors + " " + run + " --config='" + configPath + "'";
+                console.log(workerCmd);
+                exec(workerCmd,  finishWorker, finishWorker) 
+            });
+            
+            function finishWorker(e, errorStatus) {
+                counter--;
+                if (firstErrorStatus === undefined && errorStatus !== undefined) {
+                    firstErrorStatus = errorStatus;
+                }
+                if (counter !== 0) {
+                    complete();
+                }
+                else {
+                    // last worker clean everything and runs linter in case if there were no errors
+                    deleteTemporaryProjectOutput();
+                    jake.rmRf(taskConfigsFolder);
+                    if (firstErrorStatus === undefined) {
+                        runLinter();
+                        complete();
+                    }
+                    else {
+                        failWithStatus(firstErrorStatus);
+                    }
+                }
+            }
+        });
+    }
+    
+    function failWithStatus(status) {
+        fail("Process exited with code " + status);
+    }
+    
+    function finish(errorStatus) {
+        deleteTemporaryProjectOutput();
+        if (errorStatus !== undefined) {
+            failWithStatus(errorStatus);
+        }
+        else {
+            complete();
+        }
+    }
+    function runLinter() {
+        if (!lintFlag) {
+            return;
+        }
+        var lint = jake.Task['lint'];
+        lint.addListener('complete', function () {
+            complete();
+        });
+        lint.invoke();
+    }
 }
 
 var testTimeout = 20000;
 desc("Runs all the tests in parallel using the built run.js file. Optional arguments are: t[ests]=category1|category2|... d[ebug]=true.");
 task("runtests-parallel", ["build-rules", "tests", builtLocalDirectory], function() {
-    runConsoleTests('min', ['compiler', 'conformance', 'Projects', 'fourslash']);
+    runConsoleTests('min', /*runInParallel*/ true);
 }, {async: true});
 
 desc("Runs the tests using the built run.js file. Optional arguments are: t[ests]=regex r[eporter]=[list|spec|json|<more>] d[ebug]=true color[s]=false lint=true.");
 task("runtests", ["build-rules", "tests", builtLocalDirectory], function() {
-    runConsoleTests('mocha-fivemat-progress-reporter', []);
+    runConsoleTests('mocha-fivemat-progress-reporter', /*runInParallel*/ false);
 }, {async: true});
 
 desc("Generates code coverage data via instanbul");
diff --git a/src/harness/compilerRunner.ts b/src/harness/compilerRunner.ts
index 1a83f8c4582..e822b31584e 100644
--- a/src/harness/compilerRunner.ts
+++ b/src/harness/compilerRunner.ts
@@ -12,7 +12,7 @@ const enum CompilerTestType {
 
 class CompilerBaselineRunner extends RunnerBase {
     private basePath = "tests/cases";
-    private testSuiteName: string;
+    private testSuiteName: TestRunnerKind;
     private errors: boolean;
     private emit: boolean;
     private decl: boolean;
@@ -41,6 +41,14 @@ class CompilerBaselineRunner extends RunnerBase {
         this.basePath += "/" + this.testSuiteName;
     }
 
+    public kind() {
+        return this.testSuiteName;
+    }
+
+    public enumerateTestFiles() {
+        return this.enumerateFiles(this.basePath, /\.tsx?$/, { recursive: true });
+    }
+
     private makeUnitName(name: string, root: string) {
         return ts.isRootedDiskPath(name) ? name : ts.combinePaths(root, name);
     };
@@ -391,7 +399,7 @@ class CompilerBaselineRunner extends RunnerBase {
 
             // this will set up a series of describe/it blocks to run between the setup and cleanup phases
             if (this.tests.length === 0) {
-                const testFiles = this.enumerateFiles(this.basePath, /\.tsx?$/, { recursive: true });
+                const testFiles = this.enumerateTestFiles();
                 testFiles.forEach(fn => {
                     fn = fn.replace(/\\/g, "/");
                     this.checkTestCodeOutput(fn);
diff --git a/src/harness/fourslashRunner.ts b/src/harness/fourslashRunner.ts
index 0047e851fc1..d835054a868 100644
--- a/src/harness/fourslashRunner.ts
+++ b/src/harness/fourslashRunner.ts
@@ -11,7 +11,7 @@ const enum FourSlashTestType {
 
 class FourSlashRunner extends RunnerBase {
     protected basePath: string;
-    protected testSuiteName: string;
+    protected testSuiteName: TestRunnerKind;
 
     constructor(private testType: FourSlashTestType) {
         super();
@@ -35,9 +35,17 @@ class FourSlashRunner extends RunnerBase {
         }
     }
 
+    public enumerateTestFiles() {
+        return this.enumerateFiles(this.basePath, /\.ts/i, { recursive: false });
+    }
+
+    public kind() {
+        return this.testSuiteName;
+    }
+
     public initializeTests() {
         if (this.tests.length === 0) {
-            this.tests = this.enumerateFiles(this.basePath, /\.ts/i, { recursive: false });
+            this.tests = this.enumerateTestFiles();
         }
 
         describe(this.testSuiteName + " tests", () => {
diff --git a/src/harness/projectsRunner.ts b/src/harness/projectsRunner.ts
index d4e91d43efe..60a0813b05d 100644
--- a/src/harness/projectsRunner.ts
+++ b/src/harness/projectsRunner.ts
@@ -36,11 +36,19 @@ interface BatchCompileProjectTestCaseResult extends CompileProjectFilesResult {
 }
 
 class ProjectRunner extends RunnerBase {
+
+    public enumerateTestFiles() {
+        return this.enumerateFiles("tests/cases/project", /\.json$/, { recursive: true });
+    }
+
+    public kind(): TestRunnerKind {
+        return "project";
+    }
+
     public initializeTests() {
         if (this.tests.length === 0) {
-            const testFiles = this.enumerateFiles("tests/cases/project", /\.json$/, { recursive: true });
+            const testFiles = this.enumerateTestFiles();
             testFiles.forEach(fn => {
-                fn = fn.replace(/\\/g, "/");
                 this.runProjectTestCase(fn);
             });
         }
diff --git a/src/harness/runner.ts b/src/harness/runner.ts
index b56959d7e5d..1c36614e61f 100644
--- a/src/harness/runner.ts
+++ b/src/harness/runner.ts
@@ -31,18 +31,90 @@ function runTests(runners: RunnerBase[]) {
     }
 }
 
-// users can define tests to run in mytest.config that will override cmd line args, otherwise use cmd line args (test.config), otherwise no options
-let mytestconfig = "mytest.config";
-let testconfig = "test.config";
-let testConfigFile =
-    Harness.IO.fileExists(mytestconfig) ? Harness.IO.readFile(mytestconfig) :
-    (Harness.IO.fileExists(testconfig) ? Harness.IO.readFile(testconfig) : "");
+function tryGetConfig(args: string[]) {
+    const prefix = "--config=";
+    const configPath = ts.forEach(args, arg => arg.lastIndexOf(prefix, 0) === 0 && arg.substr(prefix.length));
+    // strip leading and trailing quotes from the path (necessary on Windows since shell does not do it automatically)
+    return configPath && configPath.replace(/(^[\"'])|([\"']$)/g, "");
+}
 
-if (testConfigFile !== "") {
-    const testConfig = JSON.parse(testConfigFile);
+function createRunner(kind: TestRunnerKind): RunnerBase {
+    switch (kind) {
+        case "conformance":
+            return new CompilerBaselineRunner(CompilerTestType.Conformance);
+        case "compiler":
+            return new CompilerBaselineRunner(CompilerTestType.Regressions);
+        case "fourslash":
+            return new FourSlashRunner(FourSlashTestType.Native);
+        case "fourslash-shims":
+            return new FourSlashRunner(FourSlashTestType.Shims);
+        case "fourslash-shims-pp":
+            return new FourSlashRunner(FourSlashTestType.ShimsWithPreprocess);
+        case "fourslash-server":
+            return new FourSlashRunner(FourSlashTestType.Server);
+        case "project":
+            return new ProjectRunner();
+        case "rwc":
+            return new RWCRunner();
+        case "test262":
+            return new Test262BaselineRunner();
+    }
+}
+
+// users can define tests to run in mytest.config that will override cmd line args, otherwise use cmd line args (test.config), otherwise no options
+
+const mytestconfigFileName = "mytest.config";
+const testconfigFileName = "test.config";
+
+const customConfig = tryGetConfig(Harness.IO.args());
+let testConfigContent =
+    customConfig && Harness.IO.fileExists(customConfig)
+        ? Harness.IO.readFile(customConfig)
+        : Harness.IO.fileExists(mytestconfigFileName)
+            ? Harness.IO.readFile(mytestconfigFileName)
+            : Harness.IO.fileExists(testconfigFileName) ? Harness.IO.readFile(testconfigFileName) : "";
+
+let taskConfigsFolder: string;
+let workerCount: number;
+let runUnitTests = true;
+
+interface TestConfig {
+    light?: boolean;
+    taskConfigsFolder?: string;
+    workerCount?: number;
+    tasks?: TaskSet[];
+    test?: string[];
+    runUnitTests?: boolean;
+}
+
+interface TaskSet {
+    runner: TestRunnerKind;
+    files: string[];
+}
+
+if (testConfigContent !== "") {
+    const testConfig = <TestConfig>JSON.parse(testConfigContent);
     if (testConfig.light) {
         Harness.lightMode = true;
     }
+    if (testConfig.taskConfigsFolder) {
+        taskConfigsFolder = testConfig.taskConfigsFolder;
+    }
+    if (testConfig.runUnitTests !== undefined) {
+        runUnitTests = testConfig.runUnitTests;
+    }
+    if (testConfig.workerCount) {
+        workerCount = testConfig.workerCount;
+    }
+    if (testConfig.tasks) {
+        for (const taskSet of testConfig.tasks) {
+            const runner = createRunner(taskSet.runner);
+            for (const file of taskSet.files) {
+                runner.addTest(file);
+            }
+            runners.push(runner);
+        }
+    }
 
     if (testConfig.test && testConfig.test.length > 0) {
         for (const option of testConfig.test) {
@@ -106,4 +178,41 @@ if (runners.length === 0) {
     // runners.push(new GeneratedFourslashRunner());
 }
 
-runTests(runners);
+if (taskConfigsFolder) {
+    // this instance of mocha should only partition work but not run actual tests
+    runUnitTests = false;
+    const workerConfigs: TestConfig[] = [];
+    for (let i = 0; i < workerCount; i++) {
+        // pass light mode settings to workers
+        workerConfigs.push({ light: Harness.lightMode, tasks: [] });
+    }
+
+    for (const runner of runners) {
+        const files = runner.enumerateTestFiles();
+        const chunkSize = Math.floor(files.length / workerCount) + 1; // add extra 1 to prevent missing tests due to rounding
+        for (let i = 0; i < workerCount; i++) {
+            const startPos = i * chunkSize;
+            const len = Math.min(chunkSize, files.length - startPos);
+            if (len !== 0) {
+                workerConfigs[i].tasks.push({
+                    runner: runner.kind(),
+                    files: files.slice(startPos, startPos + len)
+                });
+            }
+        }
+    }
+
+    for (let i = 0; i < workerCount; i++) {
+        const config = workerConfigs[i];
+        // use last worker to run unit tests
+        config.runUnitTests = i === workerCount - 1;
+        Harness.IO.writeFile(ts.combinePaths(taskConfigsFolder, `task-config${i}.json`), JSON.stringify(workerConfigs[i]));
+    }
+}
+else {
+    runTests(runners);
+}
+if (!runUnitTests) {
+    // patch `describe` to skip unit tests
+    describe = <any>describe.skip;
+}
\ No newline at end of file
diff --git a/src/harness/runnerbase.ts b/src/harness/runnerbase.ts
index a114e8c3201..81da0907714 100644
--- a/src/harness/runnerbase.ts
+++ b/src/harness/runnerbase.ts
@@ -1,5 +1,10 @@
 /// <reference path="harness.ts" />
 
+
+type TestRunnerKind = CompilerTestKind | FourslashTestKind | "project" | "rwc" | "test262";
+type CompilerTestKind = "conformance" | "compiler";
+type FourslashTestKind = "fourslash" | "fourslash-shims" | "fourslash-shims-pp" | "fourslash-server";
+
 abstract class RunnerBase {
     constructor() { }
 
@@ -12,9 +17,13 @@ abstract class RunnerBase {
     }
 
     public enumerateFiles(folder: string, regex?: RegExp, options?: { recursive: boolean }): string[] {
-        return Harness.IO.listFiles(Harness.userSpecifiedRoot + folder, regex, { recursive: (options ? options.recursive : false) });
+        return ts.map(Harness.IO.listFiles(Harness.userSpecifiedRoot + folder, regex, { recursive: (options ? options.recursive : false) }), ts.normalizeSlashes);
     }
 
+    abstract kind(): TestRunnerKind;
+
+    abstract enumerateTestFiles(): string[];
+
     /** Setup the runner's tests so that they are ready to be executed by the harness 
      *  The first test should be a describe/it block that sets up the harness's compiler instance appropriately
      */
diff --git a/src/harness/rwcRunner.ts b/src/harness/rwcRunner.ts
index 99b1ce8cc88..2ca69b09126 100644
--- a/src/harness/rwcRunner.ts
+++ b/src/harness/rwcRunner.ts
@@ -224,12 +224,20 @@ namespace RWC {
 class RWCRunner extends RunnerBase {
     private static sourcePath = "internal/cases/rwc/";
 
+    public enumerateTestFiles() {
+        return Harness.IO.listFiles(RWCRunner.sourcePath, /.+\.json$/);
+    }
+
+    public kind(): TestRunnerKind {
+        return "rwc";
+    }
+
     /** Setup the runner's tests so that they are ready to be executed by the harness
      *  The first test should be a describe/it block that sets up the harness's compiler instance appropriately
      */
     public initializeTests(): void {
         // Read in and evaluate the test list
-        const testList = Harness.IO.listFiles(RWCRunner.sourcePath, /.+\.json$/);
+        const testList = this.enumerateTestFiles();
         for (let i = 0; i < testList.length; i++) {
             this.runTest(testList[i]);
         }
diff --git a/src/harness/test262Runner.ts b/src/harness/test262Runner.ts
index 241af5f3d00..c44b2286b83 100644
--- a/src/harness/test262Runner.ts
+++ b/src/harness/test262Runner.ts
@@ -98,12 +98,20 @@ class Test262BaselineRunner extends RunnerBase {
         });
     }
 
+    public kind(): TestRunnerKind {
+        return "test262";
+    }
+
+    public enumerateTestFiles() {
+        return ts.map(this.enumerateFiles(Test262BaselineRunner.basePath, Test262BaselineRunner.testFileExtensionRegex, { recursive: true }), ts.normalizePath);
+    }
+
     public initializeTests() {
         // this will set up a series of describe/it blocks to run between the setup and cleanup phases
         if (this.tests.length === 0) {
-            const testFiles = this.enumerateFiles(Test262BaselineRunner.basePath, Test262BaselineRunner.testFileExtensionRegex, { recursive: true });
+            const testFiles = this.enumerateTestFiles();
             testFiles.forEach(fn => {
-                this.runTest(ts.normalizePath(fn));
+                this.runTest(fn);
             });
         }
         else {