diff --git a/packages/core/src/components/action-sheet/action-sheet.tsx b/packages/core/src/components/action-sheet/action-sheet.tsx
index 481632ebf9..62631252e7 100644
--- a/packages/core/src/components/action-sheet/action-sheet.tsx
+++ b/packages/core/src/components/action-sheet/action-sheet.tsx
@@ -146,11 +146,14 @@ export class ActionSheet {
   }
 
   buttonClass(button: ActionSheetButton): CssClassMap {
-    let customClass = button.cssClass.split(' ').filter(b => b.trim() !== '').join(' ');
-
     let buttonClass: string[] = !button.role
-      ? ['action-sheet-button', customClass]
-      : [`action-sheet-button`, `action-sheet-${button.role}`, customClass];
+      ? ['action-sheet-button']
+      : [`action-sheet-button`, `action-sheet-${button.role}`];
+
+    if (button.cssClass) {
+      let customClass = button.cssClass.split(' ').filter(b => b.trim() !== '').join(' ');
+      buttonClass.push(customClass);
+    }
 
     return buttonClass.reduce((prevValue: any, cssClass: any) => {
       prevValue[cssClass] = true;
diff --git a/packages/core/src/components/action-sheet/test/basic/index.html b/packages/core/src/components/action-sheet/test/basic/index.html
index 826d1e33f1..40809109a0 100644
--- a/packages/core/src/components/action-sheet/test/basic/index.html
+++ b/packages/core/src/components/action-sheet/test/basic/index.html
@@ -301,7 +301,7 @@
           {
             text: 'Test',
             role: 'test',
-            cssClass: 'my-cancel-button, my-custom-button customClass',
+            cssClass: 'my-cancel-button my-custom-button customClass',
             handler: () => {
               console.log('Cancel clicked');
             }
diff --git a/packages/core/src/components/alert/alert.tsx b/packages/core/src/components/alert/alert.tsx
index 32adf1bdce..2d495f7551 100644
--- a/packages/core/src/components/alert/alert.tsx
+++ b/packages/core/src/components/alert/alert.tsx
@@ -241,10 +241,12 @@ export class Alert {
   }
 
   buttonClass(button: AlertButton): CssClassMap {
-    let customClass = button.cssClass.split(' ').filter(b => b.trim() !== '').join(' ');
-    let buttonClass: string[] = !button.cssClass
-      ? ['alert-button', customClass]
-      : [`alert-button`, `${button.cssClass}`, customClass];
+    let buttonClass: string[] = ['alert-button'];
+
+    if (button.cssClass) {
+      let customClass = button.cssClass.split(' ').filter(b => b.trim() !== '').join(' ');
+      buttonClass.push(customClass);
+    }
 
     return buttonClass.reduce((prevValue: any, cssClass: any) => {
       prevValue[cssClass] = true;