diff --git a/src/lib/core/overlay/overlay-container.ts b/src/lib/core/overlay/overlay-container.ts
index 390ea3f48bcf..a97eb9a28d76 100644
--- a/src/lib/core/overlay/overlay-container.ts
+++ b/src/lib/core/overlay/overlay-container.ts
@@ -25,7 +25,9 @@ export class OverlayContainer {
   get themeClass(): string { return this._themeClass; }
   set themeClass(value: string) {
     if (this._containerElement) {
-      this._containerElement.classList.remove(this._themeClass);
+      if (this._themeClass) {
+        this._containerElement.classList.remove(this._themeClass);
+      }
 
       if (value) {
         this._containerElement.classList.add(value);
diff --git a/src/lib/core/overlay/overlay.spec.ts b/src/lib/core/overlay/overlay.spec.ts
index cc96eaa8146d..fc31e3f9d28a 100644
--- a/src/lib/core/overlay/overlay.spec.ts
+++ b/src/lib/core/overlay/overlay.spec.ts
@@ -476,6 +476,11 @@ describe('OverlayContainer theming', () => {
     expect(overlayContainerElement.classList).not.toContain('initial-theme');
     expect(overlayContainerElement.classList).toContain('new-theme');
   });
+
+  it('should not throw when switching from a blank theme', () => {
+    overlayContainer.themeClass = '';
+    expect(() => overlayContainer.themeClass = 'new-theme').not.toThrow();
+  });
 });
 
 /** Simple component for testing ComponentPortal. */