diff --git a/CHANGELOG-v3.md b/CHANGELOG-v3.md
index 25b069c3056..16204b76a89 100644
--- a/CHANGELOG-v3.md
+++ b/CHANGELOG-v3.md
@@ -4,6 +4,7 @@
 
 ### Fixed
 - Fixed a bug where the `orderBy` element query param wasn’t being respected when used in conjunction with a `with` param to eager-load elements in a specific order. ([#3109](https://github.com/craftcms/cms/issues/3109))
+- Fixed a bug where underscores were getting removed from slugs. ([#3111](https://github.com/craftcms/cms/issues/3111))
 
 ## 3.0.16 - 2018-07-17
 
diff --git a/src/helpers/StringHelper.php b/src/helpers/StringHelper.php
index 943696c9ef3..bb2d958be31 100644
--- a/src/helpers/StringHelper.php
+++ b/src/helpers/StringHelper.php
@@ -11,7 +11,6 @@
 use Stringy\Stringy as BaseStringy;
 use yii\base\Exception;
 use yii\base\InvalidConfigException;
-use yii\helpers\Inflector;
 
 /**
  * This helper class provides various multi-byte aware string related manipulation and encoding methods.
@@ -1039,9 +1038,12 @@ public static function encodeMb4(string $string): string
      */
     private static function _prepStringForCasing(string $string, bool $lower = true, bool $removePunctuation = true): array
     {
+        // Convert CamelCase to multiple words
+        $string = preg_replace('/(?<![A-Z])[A-Z]/', ' \0', $string);
+
         if ($lower) {
             // Make it lowercase
-            $string = Inflector::camel2words($string, false);
+            $string = static::toLowerCase($string);
         }
 
         if ($removePunctuation) {