diff --git a/goldens/aria/tree/testing/index.api.md b/goldens/aria/tree/testing/index.api.md
new file mode 100644
index 000000000000..1f83652e94b1
--- /dev/null
+++ b/goldens/aria/tree/testing/index.api.md
@@ -0,0 +1,57 @@
+## API Report File for "@angular/aria_tree_testing"
+
+> Do not edit this file. It is a report generated by [API Extractor](https://api-extractor.com/).
+
+```ts
+
+import { BaseHarnessFilters } from '@angular/cdk/testing';
+import { ComponentHarness } from '@angular/cdk/testing';
+import { ContentContainerComponentHarness } from '@angular/cdk/testing';
+import { HarnessPredicate } from '@angular/cdk/testing';
+
+// @public (undocumented)
+export interface TextTree {
+    // (undocumented)
+    children?: TextTree[];
+    // (undocumented)
+    text?: string;
+}
+
+// @public
+export class TreeHarness extends ComponentHarness {
+    getItems(filter?: TreeItemHarnessFilters): Promise<TreeItemHarness[]>;
+    getTreeStructure(): Promise<TextTree>;
+    // (undocumented)
+    static hostSelector: string;
+    static with(options?: TreeHarnessFilters): HarnessPredicate<TreeHarness>;
+}
+
+// @public
+export interface TreeHarnessFilters extends BaseHarnessFilters {
+}
+
+// @public
+export class TreeItemHarness extends ContentContainerComponentHarness<string> {
+    click(): Promise<void>;
+    getLevel(): Promise<number>;
+    getText(): Promise<string>;
+    // (undocumented)
+    static hostSelector: string;
+    isDisabled(): Promise<boolean>;
+    isExpanded(): Promise<boolean>;
+    isSelected(): Promise<boolean>;
+    static with(options?: TreeItemHarnessFilters): HarnessPredicate<TreeItemHarness>;
+}
+
+// @public
+export interface TreeItemHarnessFilters extends BaseHarnessFilters {
+    disabled?: boolean;
+    expanded?: boolean;
+    level?: number;
+    selected?: boolean;
+    text?: string | RegExp;
+}
+
+// (No @packageDocumentation comment for this package)
+
+```
diff --git a/src/aria/config.bzl b/src/aria/config.bzl
index 291412b5a3fb..10069d32848a 100644
--- a/src/aria/config.bzl
+++ b/src/aria/config.bzl
@@ -8,6 +8,7 @@ ARIA_ENTRYPOINTS = [
     "tabs",
     "toolbar",
     "tree",
+    "tree/testing",
     "private",
 ]
 
diff --git a/src/aria/tree/testing/BUILD.bazel b/src/aria/tree/testing/BUILD.bazel
new file mode 100644
index 000000000000..63e72fd18bdf
--- /dev/null
+++ b/src/aria/tree/testing/BUILD.bazel
@@ -0,0 +1,38 @@
+load("//tools:defaults.bzl", "ng_project", "ng_web_test_suite", "ts_project")
+
+package(default_visibility = ["//visibility:public"])
+
+ts_project(
+    name = "testing",
+    srcs = glob(
+        ["**/*.ts"],
+        exclude = ["**/*.spec.ts"],
+    ),
+    deps = [
+        "//src/cdk/testing",
+    ],
+)
+
+filegroup(
+    name = "source-files",
+    srcs = glob(["**/*.ts"]),
+)
+
+ng_project(
+    name = "unit_tests_lib",
+    testonly = True,
+    srcs = glob(["**/*.spec.ts"]),
+    deps = [
+        ":testing",
+        "//:node_modules/@angular/common",
+        "//:node_modules/@angular/core",
+        "//src/aria/tree",
+        "//src/cdk/testing",
+        "//src/cdk/testing/testbed",
+    ],
+)
+
+ng_web_test_suite(
+    name = "unit_tests",
+    deps = [":unit_tests_lib"],
+)
diff --git a/src/aria/tree/testing/index.ts b/src/aria/tree/testing/index.ts
new file mode 100644
index 000000000000..52b3c7a5156f
--- /dev/null
+++ b/src/aria/tree/testing/index.ts
@@ -0,0 +1,9 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+export * from './public-api';
diff --git a/src/aria/tree/testing/item-harness.ts b/src/aria/tree/testing/item-harness.ts
new file mode 100644
index 000000000000..204236b5adad
--- /dev/null
+++ b/src/aria/tree/testing/item-harness.ts
@@ -0,0 +1,82 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+import {ContentContainerComponentHarness, HarnessPredicate} from '@angular/cdk/testing';
+import {TreeItemHarnessFilters} from './tree-harness-filters';
+
+/** Harness for interacting with an Aria tree item. */
+export class TreeItemHarness extends ContentContainerComponentHarness<string> {
+  static hostSelector = '[ngTreeItem]';
+
+  /**
+   * Gets a `HarnessPredicate` that can be used to search for a tree item with specific attributes.
+   * @param options Options for narrowing the search
+   * @return a `HarnessPredicate` configured with the given options.
+   */
+  static with(options: TreeItemHarnessFilters = {}): HarnessPredicate<TreeItemHarness> {
+    return new HarnessPredicate(TreeItemHarness, options)
+      .addOption('text', options.text, (harness, text) =>
+        HarnessPredicate.stringMatches(harness.getText(), text),
+      )
+      .addOption(
+        'disabled',
+        options.disabled,
+        async (harness, disabled) => (await harness.isDisabled()) === disabled,
+      )
+      .addOption(
+        'expanded',
+        options.expanded,
+        async (harness, expanded) => (await harness.isExpanded()) === expanded,
+      )
+      .addOption(
+        'selected',
+        options.selected,
+        async (harness, selected) => (await harness.isSelected()) === selected,
+      )
+      .addOption(
+        'level',
+        options.level,
+        async (harness, level) => (await harness.getLevel()) === level,
+      );
+  }
+
+  /** Whether the tree item is expanded. */
+  async isExpanded(): Promise<boolean> {
+    return (await this._getHostAttribute('aria-expanded')) === 'true';
+  }
+
+  /** Whether the tree item is disabled. */
+  async isDisabled(): Promise<boolean> {
+    return (await this._getHostAttribute('aria-disabled')) === 'true';
+  }
+
+  /** Whether the tree item is selected. */
+  async isSelected(): Promise<boolean> {
+    return (await this._getHostAttribute('aria-selected')) === 'true';
+  }
+
+  /** Gets the level of the tree item. Note that this gets the aria-level and is 1 indexed. */
+  async getLevel(): Promise<number> {
+    const level = (await this._getHostAttribute('aria-level')) ?? '1';
+    return parseInt(level);
+  }
+
+  /** Gets the tree item's text. */
+  async getText(): Promise<string> {
+    return (await this.host()).text({exclude: '[ngTreeItem], [ngTreeItemGroup]'});
+  }
+
+  /** Clicks the tree item. */
+  async click(): Promise<void> {
+    return (await this.host()).click();
+  }
+
+  private async _getHostAttribute(attributeName: string): Promise<string | null> {
+    return (await this.host()).getAttribute(attributeName);
+  }
+}
diff --git a/src/aria/tree/testing/public-api.ts b/src/aria/tree/testing/public-api.ts
new file mode 100644
index 000000000000..8795f62017b1
--- /dev/null
+++ b/src/aria/tree/testing/public-api.ts
@@ -0,0 +1,11 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+export * from './item-harness';
+export * from './tree-harness';
+export * from './tree-harness-filters';
diff --git a/src/aria/tree/testing/tree-harness-filters.ts b/src/aria/tree/testing/tree-harness-filters.ts
new file mode 100644
index 000000000000..a0177eaa3bf7
--- /dev/null
+++ b/src/aria/tree/testing/tree-harness-filters.ts
@@ -0,0 +1,30 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+import {BaseHarnessFilters} from '@angular/cdk/testing';
+
+/** A set of criteria that can be used to filter a list of tree harness instances */
+export interface TreeHarnessFilters extends BaseHarnessFilters {}
+
+/** A set of criteria that can be used to filter a list of tree item harness instances. */
+export interface TreeItemHarnessFilters extends BaseHarnessFilters {
+  /** Only find instances whose text matches the given value. */
+  text?: string | RegExp;
+
+  /** Only find instances whose disabled state matches the given value. */
+  disabled?: boolean;
+
+  /** Only find instances whose expansion state matches the given value. */
+  expanded?: boolean;
+
+  /** Only find instances whose selection state matches the given value. */
+  selected?: boolean;
+
+  /** Only find instances whose level matches the given value. */
+  level?: number;
+}
diff --git a/src/aria/tree/testing/tree-harness.spec.ts b/src/aria/tree/testing/tree-harness.spec.ts
new file mode 100644
index 000000000000..2203a59c216a
--- /dev/null
+++ b/src/aria/tree/testing/tree-harness.spec.ts
@@ -0,0 +1,214 @@
+import {Component} from '@angular/core';
+import {NgTemplateOutlet} from '@angular/common';
+import {ComponentFixture, TestBed} from '@angular/core/testing';
+import {HarnessLoader} from '@angular/cdk/testing';
+import {TestbedHarnessEnvironment} from '@angular/cdk/testing/testbed';
+import {Tree, TreeItem, TreeItemGroup} from '../../tree';
+import {TreeHarness} from './tree-harness';
+
+describe('TreeHarness', () => {
+  let fixture: ComponentFixture<TreeHarnessTest>;
+  let loader: HarnessLoader;
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(TreeHarnessTest);
+    fixture.detectChanges();
+    loader = TestbedHarnessEnvironment.loader(fixture);
+  });
+
+  it('should load harness with 2 tress', async () => {
+    const trees = await loader.getAllHarnesses(TreeHarness);
+    expect(trees.length).toBe(1);
+  });
+
+  it('should get correct number of children and descendants', async () => {
+    const tree = await loader.getHarness(TreeHarness);
+    const items = await tree.getItems();
+    expect(items.length).toBe(5);
+
+    await items[0].click();
+    expect((await tree.getItems()).length).toBe(8);
+  });
+
+  it('should correctly get correct item with text', async () => {
+    const tree = await loader.getHarness(TreeHarness);
+    const items = await tree.getItems({text: /\.json$/});
+    expect(items.length).toBe(2);
+    const item = items[0];
+
+    expect(await item.getText()).toBe('angular.json');
+    expect(await item.getLevel()).toBe(1);
+    expect(await item.isDisabled()).toBe(false);
+    expect(await item.isExpanded()).toBe(false);
+  });
+
+  it('should toggle expansion', async () => {
+    const tree = await loader.getHarness(TreeHarness);
+    const item = (await tree.getItems())[0];
+
+    expect(await item.isExpanded()).toBe(false);
+    await item.click();
+    expect(await item.isExpanded()).toBe(true);
+    await item.click();
+    expect(await item.isExpanded()).toBe(false);
+  });
+
+  it('should correctly get tree structure', async () => {
+    const tree = await loader.getHarness(TreeHarness);
+
+    expect(await tree.getTreeStructure()).toEqual({
+      children: [
+        {text: 'public'},
+        {text: 'src'},
+        {text: 'angular.json'},
+        {text: 'package.json'},
+        {text: 'README.md'},
+      ],
+    });
+
+    const firstGroup = (await tree.getItems({text: 'public'}))[0];
+    await firstGroup.click();
+
+    expect(await tree.getTreeStructure()).toEqual({
+      children: [
+        {
+          text: 'public',
+          children: [{text: 'index.html'}, {text: 'favicon.ico'}, {text: 'styles.css'}],
+        },
+        {text: 'src'},
+        {text: 'angular.json'},
+        {text: 'package.json'},
+        {text: 'README.md'},
+      ],
+    });
+
+    const secondGroup = (await tree.getItems({text: 'src'}))[0];
+    await secondGroup.click();
+
+    expect(await tree.getTreeStructure()).toEqual({
+      children: [
+        {
+          text: 'public',
+          children: [{text: 'index.html'}, {text: 'favicon.ico'}, {text: 'styles.css'}],
+        },
+        {
+          text: 'src',
+          children: [
+            {text: 'app'},
+            {text: 'assets'},
+            {text: 'environments'},
+            {text: 'main.ts'},
+            {text: 'polyfills.ts'},
+            {text: 'styles.css'},
+            {text: 'test.ts'},
+          ],
+        },
+        {text: 'angular.json'},
+        {text: 'package.json'},
+        {text: 'README.md'},
+      ],
+    });
+  });
+});
+
+interface TreeNode {
+  name: string;
+  value: string;
+  children?: TreeNode[];
+  disabled?: boolean;
+  expanded?: boolean;
+}
+
+@Component({
+  template: `
+    <ul ngTree #tree="ngTree">
+      <ng-template
+        [ngTemplateOutlet]="treeNodes"
+        [ngTemplateOutletContext]="{nodes: nodes, parent: tree}"
+      />
+    </ul>
+
+    <ng-template #treeNodes let-nodes="nodes" let-parent="parent">
+      @for (node of nodes; track node.value) {
+        <li
+          ngTreeItem
+          [parent]="parent"
+          [value]="node.value"
+          [label]="node.name"
+          [disabled]="node.disabled"
+          #treeItem="ngTreeItem">
+          {{ node.name }}
+        </li>
+
+        @if (node.children) {
+          <ul role="group">
+            <ng-template ngTreeItemGroup [ownedBy]="treeItem" #group="ngTreeItemGroup">
+              <ng-template
+                [ngTemplateOutlet]="treeNodes"
+                [ngTemplateOutletContext]="{nodes: node.children, parent: group}"
+              />
+            </ng-template>
+          </ul>
+        }
+      }
+    </ng-template>
+  `,
+  imports: [Tree, TreeItem, TreeItemGroup, NgTemplateOutlet],
+})
+class TreeHarnessTest {
+  readonly nodes: TreeNode[] = [
+    {
+      name: 'public',
+      value: 'public',
+      children: [
+        {name: 'index.html', value: 'public/index.html'},
+        {name: 'favicon.ico', value: 'public/favicon.ico'},
+        {name: 'styles.css', value: 'public/styles.css'},
+      ],
+      expanded: false,
+    },
+    {
+      name: 'src',
+      value: 'src',
+      children: [
+        {
+          name: 'app',
+          value: 'src/app',
+          children: [
+            {name: 'app.component.ts', value: 'src/app/app.component.ts'},
+            {name: 'app.module.ts', value: 'src/app/app.module.ts', disabled: true},
+            {name: 'app.css', value: 'src/app/app.css'},
+          ],
+          expanded: false,
+        },
+        {
+          name: 'assets',
+          value: 'src/assets',
+          children: [{name: 'logo.png', value: 'src/assets/logo.png'}],
+          expanded: false,
+        },
+        {
+          name: 'environments',
+          value: 'src/environments',
+          children: [
+            {
+              name: 'environment.prod.ts',
+              value: 'src/environments/environment.prod.ts',
+              expanded: false,
+            },
+            {name: 'environment.ts', value: 'src/environments/environment.ts'},
+          ],
+          expanded: false,
+        },
+        {name: 'main.ts', value: 'src/main.ts'},
+        {name: 'polyfills.ts', value: 'src/polyfills.ts'},
+        {name: 'styles.css', value: 'src/styles.css', disabled: true},
+        {name: 'test.ts', value: 'src/test.ts'},
+      ],
+      expanded: false,
+    },
+    {name: 'angular.json', value: 'angular.json'},
+    {name: 'package.json', value: 'package.json'},
+    {name: 'README.md', value: 'README.md'},
+  ];
+}
diff --git a/src/aria/tree/testing/tree-harness.ts b/src/aria/tree/testing/tree-harness.ts
new file mode 100644
index 000000000000..b97c65e18637
--- /dev/null
+++ b/src/aria/tree/testing/tree-harness.ts
@@ -0,0 +1,102 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+import {ComponentHarness, HarnessPredicate, parallel} from '@angular/cdk/testing';
+import {TreeItemHarness} from './item-harness';
+import {TreeHarnessFilters, TreeItemHarnessFilters} from './tree-harness-filters';
+
+export interface TextTree {
+  text?: string;
+  children?: TextTree[];
+}
+
+/** Harness for interacting with an Aria tree in tests. */
+export class TreeHarness extends ComponentHarness {
+  static hostSelector = '[ngTree]';
+
+  /**
+   * Gets a `HarnessPredicate` that can be used to search for a tree with specific attributes.
+   * @param options Options for narrowing the search
+   * @return a `HarnessPredicate` configured with the given options.
+   */
+  static with(options: TreeHarnessFilters = {}): HarnessPredicate<TreeHarness> {
+    return new HarnessPredicate(TreeHarness, options);
+  }
+
+  /** Gets all of the items in the tree. */
+  async getItems(filter: TreeItemHarnessFilters = {}): Promise<TreeItemHarness[]> {
+    return this.locatorForAll(TreeItemHarness.with(filter))();
+  }
+
+  /**
+   * Gets an object representation for the visible tree structure
+   * If an item is under an unexpanded item it will not be included.
+   */
+  async getTreeStructure(): Promise<TextTree> {
+    const items = await this.getItems();
+    const itemInformation = await parallel(() =>
+      items.map(item => parallel(() => [item.getLevel(), item.getText(), item.isExpanded()])),
+    );
+    return this._getTreeStructure(itemInformation, 1, true);
+  }
+
+  /**
+   * Recursively collect the structured text of the tree items.
+   * @param items A list of tree items
+   * @param level The level of items that are being accounted for during this iteration
+   * @param parentExpanded Whether the parent of the first item in param items is expanded
+   */
+  private _getTreeStructure(
+    items: [number, string, boolean][],
+    level: number,
+    parentExpanded: boolean,
+  ): TextTree {
+    const result: TextTree = {};
+    for (let i = 0; i < items.length; i++) {
+      const [itemLevel, text, expanded] = items[i];
+      const nextItemLevel = items[i + 1]?.[0] ?? -1;
+
+      // Return the accumulated value for the current level once we reach a shallower level item
+      if (itemLevel < level) {
+        return result;
+      }
+      // Skip deeper level items during this iteration, they will be picked up in a later iteration
+      if (itemLevel > level) {
+        continue;
+      }
+      // Only add to representation if it is visible (parent is expanded)
+      if (parentExpanded) {
+        // Collect the data under this item according to the following rules:
+        // 1. If the next item in the list is a sibling of the current item add it to the child list
+        // 2. If the next item is a child of the current item, get the sub-tree structure for the
+        //    child and add it under this item
+        // 3. If the next item has a shallower level, we've reached the end of the child items for
+        //    the current parent.
+        if (nextItemLevel === level) {
+          this._addChildToItem(result, {text});
+        } else if (nextItemLevel > level) {
+          let children = this._getTreeStructure(
+            items.slice(i + 1),
+            nextItemLevel,
+            expanded,
+          )?.children;
+          let child = children ? {text, children} : {text};
+          this._addChildToItem(result, child);
+        } else {
+          this._addChildToItem(result, {text});
+          return result;
+        }
+      }
+    }
+    return result;
+  }
+
+  private _addChildToItem(result: TextTree, child: TextTree) {
+    result.children ? result.children.push(child) : (result.children = [child]);
+  }
+}