diff --git a/goldens/material/autocomplete/index.api.md b/goldens/material/autocomplete/index.api.md
index 9337ebaeee57..4bae890c74cd 100644
--- a/goldens/material/autocomplete/index.api.md
+++ b/goldens/material/autocomplete/index.api.md
@@ -197,6 +197,7 @@ export class MatAutocompleteTrigger implements ControlValueAccessor, AfterViewIn
     _onTouched: () => void;
     openPanel(): void;
     readonly optionSelections: Observable<MatOptionSelectionChange>;
+    readonly _overlayPanelClass: string[];
     get panelClosingActions(): Observable<MatOptionSelectionChange | null>;
     get panelOpen(): boolean;
     position: 'auto' | 'above' | 'below';
diff --git a/goldens/material/snack-bar/index.api.md b/goldens/material/snack-bar/index.api.md
index 111d667f63fc..4284125a1961 100644
--- a/goldens/material/snack-bar/index.api.md
+++ b/goldens/material/snack-bar/index.api.md
@@ -104,6 +104,8 @@ export class MatSnackBarContainer extends BasePortalOutlet implements OnDestroy
     // @deprecated
     attachDomPortal: (portal: DomPortal) => void;
     attachTemplatePortal<C>(portal: TemplatePortal<C>): EmbeddedViewRef<C>;
+    // (undocumented)
+    readonly _elementRef: ElementRef<HTMLElement>;
     enter(): void;
     exit(): Observable<void>;
     _label: ElementRef;
diff --git a/goldens/material/tooltip/index.api.md b/goldens/material/tooltip/index.api.md
index d81a8dd9a0b6..179ae42d6ffa 100644
--- a/goldens/material/tooltip/index.api.md
+++ b/goldens/material/tooltip/index.api.md
@@ -72,6 +72,8 @@ export class MatTooltip implements OnDestroy, AfterViewInit {
     ngAfterViewInit(): void;
     ngOnDestroy(): void;
     // (undocumented)
+    _overlayPanelClass: string[] | undefined;
+    // (undocumented)
     _overlayRef: OverlayRef | null;
     get position(): TooltipPosition;
     set position(value: TooltipPosition);
diff --git a/src/material/autocomplete/autocomplete-trigger.ts b/src/material/autocomplete/autocomplete-trigger.ts
index c723970f3b4f..7095fa5773a1 100644
--- a/src/material/autocomplete/autocomplete-trigger.ts
+++ b/src/material/autocomplete/autocomplete-trigger.ts
@@ -41,6 +41,7 @@ import {
   forwardRef,
   inject,
 } from '@angular/core';
+import {coerceArray} from '@angular/cdk/coercion';
 import {ControlValueAccessor, NG_VALUE_ACCESSOR} from '@angular/forms';
 import {
   MatOption,
@@ -208,6 +209,9 @@ export class MatAutocompleteTrigger
   /** Stream of keyboard events that can close the panel. */
   private readonly _closeKeyEventStream = new Subject<void>();
 
+  /** Classes to apply to the panel. Exposed as a public property for internal usage. */
+  readonly _overlayPanelClass = coerceArray(this._defaults?.overlayPanelClass || []);
+
   /**
    * Event handler for when the window is blurred. Needs to be an
    * arrow function in order to preserve the context.
@@ -905,7 +909,7 @@ export class MatAutocompleteTrigger
       direction: this._dir ?? undefined,
       hasBackdrop: this._defaults?.hasBackdrop,
       backdropClass: this._defaults?.backdropClass,
-      panelClass: this._defaults?.overlayPanelClass,
+      panelClass: this._overlayPanelClass,
       disableAnimations: this._animationsDisabled,
     });
   }
diff --git a/src/material/snack-bar/snack-bar-container.ts b/src/material/snack-bar/snack-bar-container.ts
index a7733ef7fbd3..5aa873d9ab83 100644
--- a/src/material/snack-bar/snack-bar-container.ts
+++ b/src/material/snack-bar/snack-bar-container.ts
@@ -65,7 +65,7 @@ const EXIT_ANIMATION = '_mat-snack-bar-exit';
 })
 export class MatSnackBarContainer extends BasePortalOutlet implements OnDestroy {
   private _ngZone = inject(NgZone);
-  private _elementRef = inject<ElementRef<HTMLElement>>(ElementRef);
+  readonly _elementRef = inject<ElementRef<HTMLElement>>(ElementRef);
   private _changeDetectorRef = inject(ChangeDetectorRef);
   private _platform = inject(Platform);
   protected _animationsDisabled = _animationsDisabled();
diff --git a/src/material/tooltip/tooltip.ts b/src/material/tooltip/tooltip.ts
index fdedccee645f..d54c7221cdb0 100644
--- a/src/material/tooltip/tooltip.ts
+++ b/src/material/tooltip/tooltip.ts
@@ -215,6 +215,7 @@ export class MatTooltip implements OnDestroy, AfterViewInit {
 
   _overlayRef: OverlayRef | null;
   _tooltipInstance: TooltipComponent | null;
+  _overlayPanelClass: string[] | undefined; // Used for styling internally.
 
   private _portal: ComponentPortal<TooltipComponent>;
   private _position: TooltipPosition = 'below';
@@ -525,6 +526,7 @@ export class MatTooltip implements OnDestroy, AfterViewInit {
       .getAncestorScrollContainers(this._elementRef);
 
     const overlay = this._injector.get(Overlay);
+    const panelClass = `${this._cssClassPrefix}-${PANEL_CLASS}`;
 
     // Create connected position strategy that listens for scroll events to reposition.
     const strategy = overlay
@@ -550,7 +552,7 @@ export class MatTooltip implements OnDestroy, AfterViewInit {
     this._overlayRef = overlay.create({
       direction: this._dir,
       positionStrategy: strategy,
-      panelClass: `${this._cssClassPrefix}-${PANEL_CLASS}`,
+      panelClass: this._overlayPanelClass ? [...this._overlayPanelClass, panelClass] : panelClass,
       scrollStrategy: this._injector.get(MAT_TOOLTIP_SCROLL_STRATEGY)(),
       disableAnimations: this._animationsDisabled,
     });