diff --git a/docs/pages/resources/changelog.md b/docs/pages/resources/changelog.md
index bde02402..833af4a3 100644
--- a/docs/pages/resources/changelog.md
+++ b/docs/pages/resources/changelog.md
@@ -12,6 +12,10 @@ Components with the <sl-badge variant="warning" pill>Experimental</sl-badge> bad
 
 New versions of Shoelace are released as-needed and generally occur when a critical mass of changes have accumulated. At any time, you can see what's coming in the next release by visiting [next.shoelace.style](https://next.shoelace.style).
 
+## Next
+
+- Fixed a bug in the submenu controller that prevented submenus from rendering in RTL without explicitly setting `dir` on the parent menu item [#1992]
+
 ## 2.15.1
 
 - Fixed a bug in `<sl-radio-group>` where if a click did not contain a `<sl-radio>` it would show a console error. [#2009]
diff --git a/src/components/carousel/carousel.component.ts b/src/components/carousel/carousel.component.ts
index 2a2912bc..78547576 100644
--- a/src/components/carousel/carousel.component.ts
+++ b/src/components/carousel/carousel.component.ts
@@ -153,7 +153,7 @@ export default class SlCarousel extends ShoelaceElement {
   private handleKeyDown(event: KeyboardEvent) {
     if (['ArrowLeft', 'ArrowRight', 'ArrowUp', 'ArrowDown', 'Home', 'End'].includes(event.key)) {
       const target = event.target as HTMLElement;
-      const isRtl = this.localize.dir() === 'rtl';
+      const isRtl = this.matches(':dir(rtl)');
       const isFocusInPagination = target.closest('[part~="pagination-item"]') !== null;
       const isNext =
         event.key === 'ArrowDown' || (!isRtl && event.key === 'ArrowRight') || (isRtl && event.key === 'ArrowLeft');
diff --git a/src/components/details/details.component.ts b/src/components/details/details.component.ts
index 4e9df5c9..2a38fd41 100644
--- a/src/components/details/details.component.ts
+++ b/src/components/details/details.component.ts
@@ -187,7 +187,7 @@ export default class SlDetails extends ShoelaceElement {
   }
 
   render() {
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
 
     return html`
       <details
diff --git a/src/components/image-comparer/image-comparer.component.ts b/src/components/image-comparer/image-comparer.component.ts
index 9f9cebf9..02ca1488 100644
--- a/src/components/image-comparer/image-comparer.component.ts
+++ b/src/components/image-comparer/image-comparer.component.ts
@@ -49,7 +49,7 @@ export default class SlImageComparer extends ShoelaceElement {
 
   private handleDrag(event: PointerEvent) {
     const { width } = this.base.getBoundingClientRect();
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
 
     event.preventDefault();
 
@@ -64,7 +64,7 @@ export default class SlImageComparer extends ShoelaceElement {
 
   private handleKeyDown(event: KeyboardEvent) {
     const isLtr = this.localize.dir() === 'ltr';
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
 
     if (['ArrowLeft', 'ArrowRight', 'Home', 'End'].includes(event.key)) {
       const incr = event.shiftKey ? 10 : 1;
@@ -96,7 +96,7 @@ export default class SlImageComparer extends ShoelaceElement {
   }
 
   render() {
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
 
     return html`
       <div
diff --git a/src/components/menu-item/menu-item.component.ts b/src/components/menu-item/menu-item.component.ts
index c228f574..d385854d 100644
--- a/src/components/menu-item/menu-item.component.ts
+++ b/src/components/menu-item/menu-item.component.ts
@@ -1,7 +1,6 @@
 import { classMap } from 'lit/directives/class-map.js';
 import { getTextContent, HasSlotController } from '../../internal/slot.js';
 import { html } from 'lit';
-import { LocalizeController } from '../../utilities/localize.js';
 import { property, query } from 'lit/decorators.js';
 import { SubmenuController } from './submenu-controller.js';
 import { watch } from '../../internal/watch.js';
@@ -67,9 +66,8 @@ export default class SlMenuItem extends ShoelaceElement {
   /** Draws the menu item in a disabled state, preventing selection. */
   @property({ type: Boolean, reflect: true }) disabled = false;
 
-  private readonly localize = new LocalizeController(this);
   private readonly hasSlotController = new HasSlotController(this, 'submenu');
-  private submenuController: SubmenuController = new SubmenuController(this, this.hasSlotController, this.localize);
+  private submenuController: SubmenuController = new SubmenuController(this, this.hasSlotController);
 
   connectedCallback() {
     super.connectedCallback();
@@ -155,7 +153,7 @@ export default class SlMenuItem extends ShoelaceElement {
   }
 
   render() {
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
     const isSubmenuExpanded = this.submenuController.isExpanded();
 
     return html`
diff --git a/src/components/menu-item/submenu-controller.ts b/src/components/menu-item/submenu-controller.ts
index 82f5b6fc..55ea9d47 100644
--- a/src/components/menu-item/submenu-controller.ts
+++ b/src/components/menu-item/submenu-controller.ts
@@ -1,7 +1,6 @@
 import { createRef, ref, type Ref } from 'lit/directives/ref.js';
 import { type HasSlotController } from '../../internal/slot.js';
 import { html } from 'lit';
-import { type LocalizeController } from '../../utilities/localize.js';
 import type { ReactiveController, ReactiveControllerHost } from 'lit';
 import type SlMenuItem from './menu-item.js';
 import type SlPopup from '../popup/popup.js';
@@ -15,17 +14,11 @@ export class SubmenuController implements ReactiveController {
   private isPopupConnected = false;
   private skidding = 0;
   private readonly hasSlotController: HasSlotController;
-  private readonly localize: LocalizeController;
   private readonly submenuOpenDelay = 100;
 
-  constructor(
-    host: ReactiveControllerHost & SlMenuItem,
-    hasSlotController: HasSlotController,
-    localize: LocalizeController
-  ) {
+  constructor(host: ReactiveControllerHost & SlMenuItem, hasSlotController: HasSlotController) {
     (this.host = host).addController(this);
     this.hasSlotController = hasSlotController;
-    this.localize = localize;
   }
 
   hostConnected() {
@@ -202,8 +195,7 @@ export class SubmenuController implements ReactiveController {
   private handlePopupReposition = () => {
     const submenuSlot: HTMLSlotElement | null = this.host.renderRoot.querySelector("slot[name='submenu']");
     const menu = submenuSlot?.assignedElements({ flatten: true }).filter(el => el.localName === 'sl-menu')[0];
-    const isRtl = this.localize.dir() === 'rtl';
-
+    const isRtl = this.host.matches(':dir(rtl)');
     if (!menu) {
       return;
     }
@@ -267,7 +259,7 @@ export class SubmenuController implements ReactiveController {
   }
 
   renderSubmenu() {
-    const isLtr = this.localize.dir() === 'ltr';
+    const isRtl = this.host.matches(':dir(rtl)');
 
     // Always render the slot, but conditionally render the outer <sl-popup>
     if (!this.isConnected) {
@@ -277,7 +269,7 @@ export class SubmenuController implements ReactiveController {
     return html`
       <sl-popup
         ${ref(this.popupRef)}
-        placement=${isLtr ? 'right-start' : 'left-start'}
+        placement=${isRtl ? 'left-start' : 'right-start'}
         anchor="anchor"
         flip
         flip-fallback-strategy="best-fit"
diff --git a/src/components/popup/popup.component.ts b/src/components/popup/popup.component.ts
index f5955807..7fabb4f2 100644
--- a/src/components/popup/popup.component.ts
+++ b/src/components/popup/popup.component.ts
@@ -413,7 +413,7 @@ export default class SlPopup extends ShoelaceElement {
       //
       // Source: https://github.com/floating-ui/floating-ui/blob/cb3b6ab07f95275730d3e6e46c702f8d4908b55c/packages/dom/src/utils/getDocumentRect.ts#L31
       //
-      const isRtl = getComputedStyle(this).direction === 'rtl';
+      const isRtl = this.matches(':dir(rtl)');
       const staticSide = { top: 'bottom', right: 'left', bottom: 'top', left: 'right' }[placement.split('-')[0]]!;
 
       this.setAttribute('data-current-placement', placement);
diff --git a/src/components/range/range.component.ts b/src/components/range/range.component.ts
index c00f1967..b3b38532 100644
--- a/src/components/range/range.component.ts
+++ b/src/components/range/range.component.ts
@@ -175,7 +175,7 @@ export default class SlRange extends ShoelaceElement implements ShoelaceFormCont
       const inputWidth = this.input.offsetWidth;
       const tooltipWidth = this.output.offsetWidth;
       const thumbSize = getComputedStyle(this.input).getPropertyValue('--thumb-size');
-      const isRtl = this.localize.dir() === 'rtl';
+      const isRtl = this.matches(':dir(rtl)');
       const percentAsWidth = inputWidth * percent;
 
       // The calculations are used to "guess" where the thumb is located. Since we're using the native range control
diff --git a/src/components/rating/rating.component.ts b/src/components/rating/rating.component.ts
index 4279cdd5..f900714c 100644
--- a/src/components/rating/rating.component.ts
+++ b/src/components/rating/rating.component.ts
@@ -80,7 +80,7 @@ export default class SlRating extends ShoelaceElement {
   }
 
   private getValueFromXCoordinate(coordinate: number) {
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
     const { left, right, width } = this.rating.getBoundingClientRect();
     const value = isRtl
       ? this.roundToPrecision(((right - coordinate) / width) * this.max, this.precision)
@@ -109,7 +109,7 @@ export default class SlRating extends ShoelaceElement {
 
   private handleKeyDown(event: KeyboardEvent) {
     const isLtr = this.localize.dir() === 'ltr';
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
     const oldValue = this.value;
 
     if (this.disabled || this.readonly) {
@@ -214,7 +214,7 @@ export default class SlRating extends ShoelaceElement {
   }
 
   render() {
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
     const counter = Array.from(Array(this.max).keys());
     let displayValue = 0;
 
diff --git a/src/components/split-panel/split-panel.component.ts b/src/components/split-panel/split-panel.component.ts
index bf8af30d..c61d014a 100644
--- a/src/components/split-panel/split-panel.component.ts
+++ b/src/components/split-panel/split-panel.component.ts
@@ -102,7 +102,7 @@ export default class SlSplitPanel extends ShoelaceElement {
   }
 
   private handleDrag(event: PointerEvent) {
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
 
     if (this.disabled) {
       return;
@@ -223,7 +223,7 @@ export default class SlSplitPanel extends ShoelaceElement {
   render() {
     const gridTemplate = this.vertical ? 'gridTemplateRows' : 'gridTemplateColumns';
     const gridTemplateAlt = this.vertical ? 'gridTemplateColumns' : 'gridTemplateRows';
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
     const primary = `
       clamp(
         0%,
diff --git a/src/components/tab-group/tab-group.component.ts b/src/components/tab-group/tab-group.component.ts
index 28607628..be582806 100644
--- a/src/components/tab-group/tab-group.component.ts
+++ b/src/components/tab-group/tab-group.component.ts
@@ -177,7 +177,7 @@ export default class SlTabGroup extends ShoelaceElement {
     // Move focus left or right
     if (['ArrowLeft', 'ArrowRight', 'ArrowUp', 'ArrowDown', 'Home', 'End'].includes(event.key)) {
       const activeEl = this.tabs.find(t => t.matches(':focus'));
-      const isRtl = this.localize.dir() === 'rtl';
+      const isRtl = this.matches(':dir(rtl)');
 
       if (activeEl?.tagName.toLowerCase() === 'sl-tab') {
         let index = this.tabs.indexOf(activeEl);
@@ -292,7 +292,7 @@ export default class SlTabGroup extends ShoelaceElement {
 
     const width = currentTab.clientWidth;
     const height = currentTab.clientHeight;
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
 
     // We can't used offsetLeft/offsetTop here due to a shadow parent issue where neither can getBoundingClientRect
     // because it provides invalid values for animating elements: https://bugs.chromium.org/p/chromium/issues/detail?id=920069
@@ -370,7 +370,7 @@ export default class SlTabGroup extends ShoelaceElement {
   }
 
   render() {
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
 
     return html`
       <div
diff --git a/src/components/tree-item/tree-item.component.ts b/src/components/tree-item/tree-item.component.ts
index 8b1cbffb..9310f298 100644
--- a/src/components/tree-item/tree-item.component.ts
+++ b/src/components/tree-item/tree-item.component.ts
@@ -223,7 +223,7 @@ export default class SlTreeItem extends ShoelaceElement {
   }
 
   render() {
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
     const showExpandButton = !this.loading && (!this.isLeaf || this.lazy);
 
     return html`
diff --git a/src/components/tree/tree.component.ts b/src/components/tree/tree.component.ts
index 28f47683..57556e3a 100644
--- a/src/components/tree/tree.component.ts
+++ b/src/components/tree/tree.component.ts
@@ -226,7 +226,7 @@ export default class SlTree extends ShoelaceElement {
 
     const items = this.getFocusableItems();
     const isLtr = this.localize.dir() === 'ltr';
-    const isRtl = this.localize.dir() === 'rtl';
+    const isRtl = this.matches(':dir(rtl)');
 
     if (items.length > 0) {
       event.preventDefault();