diff --git a/.scss-lint.yml b/.scss-lint.yml
index db234ad739c..acf04bf0735 100644
--- a/.scss-lint.yml
+++ b/.scss-lint.yml
@@ -10,7 +10,7 @@ linters:
   # Reports when you use improper spacing around ! (the "bang") in !default,
   # !global, !important, and !optional flags.
   BangFormat:
-    enabled: false
+    enabled: true
 
   # Whether or not to prefer `border: 0` over `border: none`.
   BorderZero:
diff --git a/app/assets/stylesheets/framework/dropdowns.scss b/app/assets/stylesheets/framework/dropdowns.scss
index dc4ed42544f..b6b4fc98656 100644
--- a/app/assets/stylesheets/framework/dropdowns.scss
+++ b/app/assets/stylesheets/framework/dropdowns.scss
@@ -675,8 +675,8 @@
   }
 
   .pika-single {
-    position: relative!important;
-    top: 0!important;
+    position: relative !important;
+    top: 0 !important;
     border: 0;
     box-shadow: none;
   }
diff --git a/app/assets/stylesheets/framework/header.scss b/app/assets/stylesheets/framework/header.scss
index 5bd6c095109..20fb10c28d4 100644
--- a/app/assets/stylesheets/framework/header.scss
+++ b/app/assets/stylesheets/framework/header.scss
@@ -330,7 +330,7 @@ header {
       padding-left: 5px;
 
       .nav > li:not(.hidden-xs) {
-        display: table-cell!important;
+        display: table-cell !important;
         width: 25%;
 
         a {
diff --git a/app/assets/stylesheets/pages/boards.scss b/app/assets/stylesheets/pages/boards.scss
index 85109fec91a..df858cffe09 100644
--- a/app/assets/stylesheets/pages/boards.scss
+++ b/app/assets/stylesheets/pages/boards.scss
@@ -11,7 +11,7 @@
 
 .is-dragging {
   // Important because plugin sets inline CSS
-  opacity: 1!important;
+  opacity: 1 !important;
 
   * {
     -webkit-user-select: none;
@@ -19,8 +19,8 @@
     -ms-user-select: none;
     user-select: none;
     // !important to make sure no style can override this when dragging
-    cursor: -webkit-grabbing!important;
-    cursor: grabbing!important;
+    cursor: -webkit-grabbing !important;
+    cursor: grabbing !important;
   }
 }
 
diff --git a/app/assets/stylesheets/pages/pipeline_schedules.scss b/app/assets/stylesheets/pages/pipeline_schedules.scss
index dc719a6ba94..7f893bcf68b 100644
--- a/app/assets/stylesheets/pages/pipeline_schedules.scss
+++ b/app/assets/stylesheets/pages/pipeline_schedules.scss
@@ -1,7 +1,7 @@
 .js-pipeline-schedule-form {
   .dropdown-select,
   .dropdown-menu-toggle {
-    width: 100%!important;
+    width: 100% !important;
   }
 
   .gl-field-error {
diff --git a/app/assets/stylesheets/print.scss b/app/assets/stylesheets/print.scss
index 136d0c79467..113e6e86bb5 100644
--- a/app/assets/stylesheets/print.scss
+++ b/app/assets/stylesheets/print.scss
@@ -37,7 +37,7 @@ ul.notes-form,
 .issuable-details .content-block-small,
 .edit-link,
 .note-action-button {
-  display: none!important;
+  display: none !important;
 }
 
 pre {
diff --git a/changelogs/unreleased/enable-scss-lint-bang-format.yml b/changelogs/unreleased/enable-scss-lint-bang-format.yml
new file mode 100644
index 00000000000..0b73760198e
--- /dev/null
+++ b/changelogs/unreleased/enable-scss-lint-bang-format.yml
@@ -0,0 +1,4 @@
+---
+title: Enable BangFormat in scss-lint [ci skip]
+merge_request: 12815
+author: Takuya Noguchi