diff --git a/src/components/ha-code-editor.ts b/src/components/ha-code-editor.ts
index 190b456fbd..be825c2b42 100644
--- a/src/components/ha-code-editor.ts
+++ b/src/components/ha-code-editor.ts
@@ -6,6 +6,7 @@ import type {
 } from "@codemirror/autocomplete";
 import type { Extension, TransactionSpec } from "@codemirror/state";
 import type { EditorView, KeyBinding, ViewUpdate } from "@codemirror/view";
+import { mdiArrowExpand, mdiArrowCollapse } from "@mdi/js";
 import type { HassEntities } from "home-assistant-js-websocket";
 import type { PropertyValues } from "lit";
 import { css, ReactiveElement } from "lit";
@@ -15,6 +16,7 @@ import { fireEvent } from "../common/dom/fire_event";
 import { stopPropagation } from "../common/dom/stop_propagation";
 import type { HomeAssistant } from "../types";
 import "./ha-icon";
+import "./ha-icon-button";
 
 declare global {
   interface HASSDomEvents {
@@ -59,8 +61,13 @@ export class HaCodeEditor extends ReactiveElement {
 
   @property({ type: Boolean }) public error = false;
 
+  @property({ type: Boolean, attribute: "enable-fullscreen" })
+  public enableFullscreen = true;
+
   @state() private _value = "";
 
+  @state() private _isFullscreen = false;
+
   // eslint-disable-next-line @typescript-eslint/consistent-type-imports
   private _loadedCodeMirror?: typeof import("../resources/codemirror");
 
@@ -92,6 +99,7 @@ export class HaCodeEditor extends ReactiveElement {
       this.requestUpdate();
     }
     this.addEventListener("keydown", stopPropagation);
+    this.addEventListener("keydown", this._handleKeyDown);
     // This is unreachable as editor will not exist yet,
     // but focus should not behave like this for good a11y.
     // (@steverep to fix in autofocus PR)
@@ -106,6 +114,10 @@ export class HaCodeEditor extends ReactiveElement {
   public disconnectedCallback() {
     super.disconnectedCallback();
     this.removeEventListener("keydown", stopPropagation);
+    this.removeEventListener("keydown", this._handleKeyDown);
+    if (this._isFullscreen) {
+      this._toggleFullscreen();
+    }
     this.updateComplete.then(() => {
       this.codemirror!.destroy();
       delete this.codemirror;
@@ -164,6 +176,12 @@ export class HaCodeEditor extends ReactiveElement {
     if (changedProps.has("error")) {
       this.classList.toggle("error-state", this.error);
     }
+    if (changedProps.has("_isFullscreen")) {
+      this.classList.toggle("fullscreen", this._isFullscreen);
+    }
+    if (changedProps.has("enableFullscreen")) {
+      this._updateFullscreenButton();
+    }
   }
 
   private get _mode() {
@@ -238,8 +256,74 @@ export class HaCodeEditor extends ReactiveElement {
       }),
       parent: this.renderRoot,
     });
+
+    this._updateFullscreenButton();
   }
 
+  private _updateFullscreenButton() {
+    const existingButton = this.renderRoot.querySelector(".fullscreen-button");
+
+    if (!this.enableFullscreen) {
+      // Remove button if it exists and fullscreen is disabled
+      if (existingButton) {
+        existingButton.remove();
+      }
+      // Exit fullscreen if currently in fullscreen mode
+      if (this._isFullscreen) {
+        this._isFullscreen = false;
+      }
+      return;
+    }
+
+    // Create button if it doesn't exist
+    if (!existingButton) {
+      const button = document.createElement("ha-icon-button");
+      (button as any).path = this._isFullscreen
+        ? mdiArrowCollapse
+        : mdiArrowExpand;
+      button.setAttribute(
+        "label",
+        this._isFullscreen ? "Exit fullscreen" : "Enter fullscreen"
+      );
+      button.classList.add("fullscreen-button");
+      // Use bound method to ensure proper this context
+      button.addEventListener("click", this._handleFullscreenClick);
+      this.renderRoot.appendChild(button);
+    } else {
+      // Update existing button
+      (existingButton as any).path = this._isFullscreen
+        ? mdiArrowCollapse
+        : mdiArrowExpand;
+      existingButton.setAttribute(
+        "label",
+        this._isFullscreen ? "Exit fullscreen" : "Enter fullscreen"
+      );
+    }
+  }
+
+  private _handleFullscreenClick = (e: Event) => {
+    e.preventDefault();
+    e.stopPropagation();
+    this._toggleFullscreen();
+  };
+
+  private _toggleFullscreen() {
+    this._isFullscreen = !this._isFullscreen;
+    this._updateFullscreenButton();
+  }
+
+  private _handleKeyDown = (e: KeyboardEvent) => {
+    if (this._isFullscreen && e.key === "Escape") {
+      e.preventDefault();
+      e.stopPropagation();
+      this._toggleFullscreen();
+    } else if (e.key === "F11" && this.enableFullscreen) {
+      e.preventDefault();
+      e.stopPropagation();
+      this._toggleFullscreen();
+    }
+  };
+
   private _getStates = memoizeOne((states: HassEntities): Completion[] => {
     if (!states) {
       return [];
@@ -460,9 +544,78 @@ export class HaCodeEditor extends ReactiveElement {
   };
 
   static styles = css`
+    :host {
+      position: relative;
+      display: block;
+    }
+
     :host(.error-state) .cm-gutters {
       border-color: var(--error-state-color, red);
     }
+
+    .fullscreen-button {
+      position: absolute;
+      top: 8px;
+      right: 8px;
+      z-index: 10;
+      color: var(--secondary-text-color);
+      background-color: var(--card-background-color);
+      border-radius: 50%;
+      opacity: 0.6;
+      transition: opacity 0.2s;
+      --mdc-icon-button-size: 32px;
+      --mdc-icon-size: 18px;
+      /* Ensure button is clickable on iOS */
+      cursor: pointer;
+      -webkit-tap-highlight-color: transparent;
+      touch-action: manipulation;
+    }
+
+    .fullscreen-button:hover,
+    .fullscreen-button:active {
+      opacity: 1;
+    }
+
+    @media (hover: none) {
+      .fullscreen-button {
+        opacity: 0.8;
+      }
+    }
+
+    :host(.fullscreen) {
+      position: fixed !important;
+      top: var(--header-height, 56px) !important;
+      left: 0 !important;
+      right: 0 !important;
+      bottom: 0 !important;
+      z-index: 9999 !important;
+      background-color: var(--primary-background-color) !important;
+      margin: 0 !important;
+      padding: 16px !important;
+      /* Respect iOS safe areas while accounting for header */
+      padding-top: max(16px, env(safe-area-inset-top)) !important;
+      padding-left: max(16px, env(safe-area-inset-left)) !important;
+      padding-right: max(16px, env(safe-area-inset-right)) !important;
+      padding-bottom: max(16px, env(safe-area-inset-bottom)) !important;
+      box-sizing: border-box !important;
+      display: flex !important;
+      flex-direction: column !important;
+    }
+
+    :host(.fullscreen) .cm-editor {
+      height: 100% !important;
+      max-height: 100% !important;
+      border-radius: 0 !important;
+    }
+
+    :host(.fullscreen) .fullscreen-button {
+      position: fixed;
+      top: calc(
+        var(--header-height, 56px) + max(8px, env(safe-area-inset-top))
+      );
+      right: max(24px, calc(env(safe-area-inset-right) + 8px));
+      z-index: 10000;
+    }
   `;
 }