diff --git a/src/UIShell/SideNav/SideNav.svelte b/src/UIShell/SideNav/SideNav.svelte
index 4f1e0b02..ce2649ba 100644
--- a/src/UIShell/SideNav/SideNav.svelte
+++ b/src/UIShell/SideNav/SideNav.svelte
@@ -33,7 +33,7 @@
   class:bx--side-nav="{true}"
   class:bx--side-nav--ux="{true}"
   class:bx--side-nav--expanded="{isOpen}"
-  class:bx--side-nav--collapsed="{!isOpen && !fixed}"
+  class:bx--side-nav--collapsed="{fixed ? !isOpen && fixed : !isOpen}"
   {...$$restProps}
 >
   <slot />