diff --git a/README.md b/README.md
index d7b85ac23..6911e0d32 100644
--- a/README.md
+++ b/README.md
@@ -140,6 +140,7 @@
 * [`reverseString`](#reversestring)
 * [`sortCharactersInString`](#sortcharactersinstring)
 * [`toCamelCase`](#tocamelcase)
+* [`toSnakeCase`](#tosnakecase)
 * [`truncateString`](#truncatestring)
 * [`words`](#words)
 
@@ -1911,6 +1912,23 @@ const toCamelCase = str =>
 
 [⬆ back to top](#table-of-contents)
 
+### toSnakeCase
+
+Converts a string to snakecase.
+
+Use `replace()` to add underscores before capital letters, convert `toLowerCase()`, then `replace()` hyphens and spaces with underscores.
+
+```js
+const toSnakeCase = str =>
+  str.replace(/[A-Z]/g, (match, p1, p2, offset) => '_' + match).toLowerCase().replace(/[\s-]+/g,'_');
+// toSnakeCase("camelCase") -> 'camel_case'
+// toSnakeCase("some text") -> 'some_text'
+// toSnakeCase("some-javascript-property") -> 'some_javascript_property'
+// toSnakeCase("some-mixed_string With spaces_underscores-and-hyphens") -> 'some_mixed_string_with_spaces_underscores_and_hyphens'
+```
+
+[⬆ back to top](#table-of-contents)
+
 ### truncateString
 
 Truncates a string up to a specified length.
diff --git a/docs/index.html b/docs/index.html
index 551066214..decde3adc 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -168,6 +168,7 @@
 <a class="sublink-1" href="#reversestring">reverseString</a>
 <a class="sublink-1" href="#sortcharactersinstring">sortCharactersInString</a>
 <a class="sublink-1" href="#tocamelcase">toCamelCase</a>
+<a class="sublink-1" href="#tosnakecase">toSnakeCase</a>
 <a class="sublink-1" href="#truncatestring">truncateString</a>
 <a class="sublink-1" href="#words">words</a>
 
@@ -1178,6 +1179,16 @@ Combine characters to get a string using <code>join('')</code>.</p>
 // toCamelCase(&quot;some-javascript-property&quot;) -&gt; 'someJavascriptProperty'
 // toCamelCase(&quot;some-mixed_string with spaces_underscores-and-hyphens&quot;) -&gt; 'someMixedStringWithSpacesUnderscoresAndHyphens'
 </code></pre>
+</div></div><br/><div class="card fluid"><div class="section double-padded"><h3 id="tosnakecase">toSnakeCase</h3></div><div class="section double-padded">
+<p>Converts a string to snakecase.</p>
+<p>Use <code>replace()</code> to add underscores before capital letters, convert <code>toLowerCase()</code>, then <code>replace()</code> hyphens and spaces with underscores.</p>
+<pre><code class="language-js">const toSnakeCase = str =&gt;
+  str.replace(/[A-Z]/g, (match, p1, p2, offset) =&gt; '_' + match).toLowerCase().replace(/[\s-]+/g,'_');
+// toSnakeCase(&quot;camelCase&quot;) -&gt; 'camel_case'
+// toSnakeCase(&quot;some text&quot;) -&gt; 'some_text'
+// toSnakeCase(&quot;some-javascript-property&quot;) -&gt; 'some_javascript_property'
+// toSnakeCase(&quot;some-mixed_string With spaces_underscores-and-hyphens&quot;) -&gt; 'some_mixed_string_with_spaces_underscores_and_hyphens'
+</code></pre>
 </div></div><br/><div class="card fluid"><div class="section double-padded"><h3 id="truncatestring">truncateString</h3></div><div class="section double-padded">
 <p>Truncates a string up to a specified length.</p>
 <p>Determine if the string's <code>length</code> is greater than <code>num</code>.