diff --git a/scss/utilities/_spacing.scss b/scss/utilities/_spacing.scss
index b7ff044b6d..c81a6aa887 100644
--- a/scss/utilities/_spacing.scss
+++ b/scss/utilities/_spacing.scss
@@ -4,7 +4,7 @@
 
 // Margin and Padding
 
-.m-x-auto {
+.mx-auto {
   margin-right: auto !important;
   margin-left:  auto !important;
 }
@@ -14,18 +14,18 @@
     $length-x:   map-get($lengths, x);
     $length-y:   map-get($lengths, y);
 
-    .#{$abbrev}-a-#{$size} { #{$prop}:        $length-y $length-x !important; } // a = All sides
-    .#{$abbrev}-t-#{$size} { #{$prop}-top:    $length-y !important; }
-    .#{$abbrev}-r-#{$size} { #{$prop}-right:  $length-x !important; }
-    .#{$abbrev}-b-#{$size} { #{$prop}-bottom: $length-y !important; }
-    .#{$abbrev}-l-#{$size} { #{$prop}-left:   $length-x !important; }
+    .#{$abbrev}-#{$size} { #{$prop}:        $length-y $length-x !important; } // a = All sides
+    .#{$abbrev}t-#{$size} { #{$prop}-top:    $length-y !important; }
+    .#{$abbrev}r-#{$size} { #{$prop}-right:  $length-x !important; }
+    .#{$abbrev}b-#{$size} { #{$prop}-bottom: $length-y !important; }
+    .#{$abbrev}l-#{$size} { #{$prop}-left:   $length-x !important; }
 
     // Axes
-    .#{$abbrev}-x-#{$size} {
+    .#{$abbrev}x-#{$size} {
       #{$prop}-right:  $length-x !important;
       #{$prop}-left:   $length-x !important;
     }
-    .#{$abbrev}-y-#{$size} {
+    .#{$abbrev}y-#{$size} {
       #{$prop}-top:    $length-y !important;
       #{$prop}-bottom: $length-y !important;
     }