--- /dev/null
+var toString = require('./toString');
+
+/**
+ * Converts `string`, as a whole, to lower case just like
+ * [String#toLowerCase](https://mdn.io/toLowerCase).
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category String
+ * @param {string} [string=''] The string to convert.
+ * @returns {string} Returns the lower cased string.
+ * @example
+ *
+ * _.toLower('--Foo-Bar--');
+ * // => '--foo-bar--'
+ *
+ * _.toLower('fooBar');
+ * // => 'foobar'
+ *
+ * _.toLower('__FOO_BAR__');
+ * // => '__foo_bar__'
+ */
+function toLower(value) {
+ return toString(value).toLowerCase();
+}
+
+module.exports = toLower;