diff --git a/src/configurationHelper.ts b/src/configurationHelper.ts
index bef16225..c4546866 100644
--- a/src/configurationHelper.ts
+++ b/src/configurationHelper.ts
@@ -81,15 +81,60 @@ function writeDojoRcConfig(config: Config, indent: string | number) {
 	writeFileSync(dojoRcPath, json);
 }
 
+function mergeConfigs(config: Config) {
+	const configs = getExtendingConfigs(config);
+	let mergedConfig: Config = config;
+	if (configs.length) {
+		let baseConfig: Config;
+		while ((baseConfig = configs.shift())) {
+			mergedConfig = merge(mergedConfig, baseConfig);
+		}
+	}
+	return mergedConfig;
+}
+
+function getExtendingConfigs(config: Config) {
+	const configs = [];
+	let extendingConfig = config;
+	while (typeof extendingConfig.extends === 'string') {
+		const extendedConfig = JSON.parse(readFileSync(extendingConfig.extends, 'utf8'));
+		configs.push(extendedConfig);
+		extendingConfig = extendedConfig;
+	}
+	return configs;
+}
+
+function merge(extendingObj: { [key: string]: any }, baseObj: { [key: string]: any }) {
+	Object.keys(baseObj).forEach((prop) => {
+		if (extendingObj[prop] === undefined) {
+			extendingObj[prop] = baseObj[prop];
+		} else if (isObject(baseObj[prop])) {
+			extendingObj[prop] = merge(extendingObj[prop], baseObj[prop]);
+		}
+	});
+	return extendingObj;
+}
+
+function isObject(item: any) {
+	return item && typeof item === 'object' && !Array.isArray(item);
+}
+
+function checkIfConfigExtends(config?: Config) {
+	if (config && config.extends) {
+		config = mergeConfigs(config);
+	}
+	return config;
+}
+
 export function getConfig(): Config | undefined {
 	const { packageJsonConfig, dojoRcConfig } = parseConfigs();
 	const hasPackageConfig = typeof packageJsonConfig === 'object';
 	const hasDojoRcConfig = typeof dojoRcConfig === 'object';
 
 	if (!hasDojoRcConfig && hasPackageConfig) {
-		return packageJsonConfig;
+		return checkIfConfigExtends(packageJsonConfig);
 	} else {
-		return dojoRcConfig;
+		return checkIfConfigExtends(dojoRcConfig);
 	}
 }
 
diff --git a/tests/unit/configurationHelper.ts b/tests/unit/configurationHelper.ts
index 179d346e..4a48d657 100644
--- a/tests/unit/configurationHelper.ts
+++ b/tests/unit/configurationHelper.ts
@@ -185,6 +185,88 @@ registerSuite('Configuration Helper', {
 				assert.equal(mockFs.readFileSync.firstCall.args[0], dojoRcPath);
 				assert.deepEqual(config, existingConfig);
 			},
+			'Should shallow extend configs correctly'() {
+				mockFs.existsSync.onCall(0).returns(true);
+				mockFs.existsSync.onCall(1).returns(false);
+				mockFs.readFileSync.onCall(0).returns(
+					JSON.stringify({
+						extends: './path/to/dojorc/to/.extend',
+						'testGroupName-testCommandName': {
+							prop: 'config'
+						}
+					})
+				);
+				mockFs.readFileSync.onCall(1).returns(
+					JSON.stringify({
+						'testGroupName-testCommandName': {
+							prop: 'config-extended'
+						}
+					})
+				);
+				const config = configurationHelper.sandbox('testGroupName', 'testCommandName').get();
+				assert.isTrue(mockFs.readFileSync.calledTwice);
+				assert.equal(mockFs.readFileSync.firstCall.args[0], dojoRcPath);
+				assert.deepEqual(config, {
+					prop: 'config'
+				});
+			},
+			'Supports deep extension of configs correctly'() {
+				mockFs.existsSync.onCall(0).returns(true);
+				mockFs.existsSync.onCall(1).returns(false);
+				mockFs.readFileSync.onCall(0).returns(
+					JSON.stringify({
+						extends: './path/to/dojorc/to/.extend',
+						'testGroupName-testCommandName': {
+							prop: 'config'
+						}
+					})
+				);
+				mockFs.readFileSync.onCall(1).returns(
+					JSON.stringify({
+						extends: './path/to/dojorc/to/.extend1',
+						'testGroupName-testCommandName': {
+							prop: 'config-extended-1',
+							prop1: 'config-extended-1',
+							prop3: {
+								innerProp: 'config-inner-prop',
+								innerProp1: {
+									deepProp: 'config-deep-prop',
+									deepProp1: 'config-deep-prop'
+								}
+							}
+						}
+					})
+				);
+				mockFs.readFileSync.onCall(2).returns(
+					JSON.stringify({
+						'testGroupName-testCommandName': {
+							prop: 'config-extended-2',
+							prop2: 'config-extended-2',
+							prop3: {
+								innerProp: 'config-inner-prop-1',
+								innerProp1: {
+									deepProp: 'config-deep-prop'
+								}
+							}
+						}
+					})
+				);
+				const config = configurationHelper.sandbox('testGroupName', 'testCommandName').get();
+				assert.equal(mockFs.readFileSync.callCount, 3);
+				assert.equal(mockFs.readFileSync.firstCall.args[0], dojoRcPath);
+				assert.deepEqual(config, {
+					prop: 'config',
+					prop1: 'config-extended-1',
+					prop2: 'config-extended-2',
+					prop3: {
+						innerProp: 'config-inner-prop',
+						innerProp1: {
+							deepProp: 'config-deep-prop',
+							deepProp1: 'config-deep-prop'
+						}
+					}
+				});
+			},
 			'Should accept and ignore commandName parameter'() {
 				const newConfig = { foo: 'bar' };
 				mockFs.readFileSync = sinon.stub().returns(JSON.stringify({ 'testGroupName-testCommandName': {} }));