diff --git a/packages/components/CHANGELOG.md b/packages/components/CHANGELOG.md
index 72e22bbe0c1178..5b9aaeea25a2c1 100644
--- a/packages/components/CHANGELOG.md
+++ b/packages/components/CHANGELOG.md
@@ -25,7 +25,7 @@
 -   `Tabs`: improve controlled mode focus handling and keyboard navigation ([#57696](https://github.com/WordPress/gutenberg/pull/57696)).
 -   `Tabs`: prevent internal focus from updating too early ([#58625](https://github.com/WordPress/gutenberg/pull/58625)).
 -   Expand theming support in the `COLORS` variable object ([#58097](https://github.com/WordPress/gutenberg/pull/58097)).
--   `CustomSelect`: disable `virtualFocus` to fix issue for screenreaders ([#58585](https://github.com/WordPress/gutenberg/pull/58585))
+-   `CustomSelect`: disable `virtualFocus` to fix issue for screenreaders ([#58585](https://github.com/WordPress/gutenberg/pull/58585)).
 
 ### Enhancements
 
@@ -35,6 +35,7 @@
 
 -   `Composite`: Removing Reakit `Composite` implementation ([#58620](https://github.com/WordPress/gutenberg/pull/58620)).
 -   Removing Reakit as a dependency of the components package ([#58631](https://github.com/WordPress/gutenberg/pull/58631)).
+-   `CustomSelect`: add unit tests ([#58583](https://github.com/WordPress/gutenberg/pull/58583)).
 
 ## 25.16.0 (2024-01-24)
 
diff --git a/packages/components/src/custom-select-control-v2/test/index.tsx b/packages/components/src/custom-select-control-v2/test/index.tsx
new file mode 100644
index 00000000000000..a707a56e4d724a
--- /dev/null
+++ b/packages/components/src/custom-select-control-v2/test/index.tsx
@@ -0,0 +1,219 @@
+/**
+ * External dependencies
+ */
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+
+/**
+ * WordPress dependencies
+ */
+import { useState } from '@wordpress/element';
+
+/**
+ * Internal dependencies
+ */
+import { CustomSelect, CustomSelectItem } from '..';
+import type { CustomSelectProps } from '../types';
+
+const ControlledCustomSelect = ( props: CustomSelectProps ) => {
+	const [ value, setValue ] = useState< string | string[] >();
+	return (
+		<CustomSelect
+			{ ...props }
+			onChange={ ( nextValue ) => {
+				setValue( nextValue );
+				props.onChange?.( nextValue );
+			} }
+			value={ value }
+		/>
+	);
+};
+
+describe.each( [
+	[ 'uncontrolled', CustomSelect ],
+	[ 'controlled', ControlledCustomSelect ],
+] )( 'CustomSelect %s', ( ...modeAndComponent ) => {
+	const [ , Component ] = modeAndComponent;
+
+	describe( 'Multiple selection', () => {
+		it( 'Should be able to select multiple items when provided an array', async () => {
+			const user = userEvent.setup();
+			const onChangeMock = jest.fn();
+
+			// initial selection as defaultValue
+			const defaultValues = [
+				'incandescent glow',
+				'ultraviolet morning light',
+			];
+
+			render(
+				<Component
+					defaultValue={ defaultValues }
+					onChange={ onChangeMock }
+					label="Multi-select"
+				>
+					{ [
+						'aurora borealis green',
+						'flamingo pink sunrise',
+						'incandescent glow',
+						'rose blush',
+						'ultraviolet morning light',
+					].map( ( item ) => (
+						<CustomSelectItem key={ item } value={ item }>
+							{ item }
+						</CustomSelectItem>
+					) ) }
+				</Component>
+			);
+
+			const currentSelectedItem = screen.getByRole( 'combobox', {
+				expanded: false,
+			} );
+
+			// ensure more than one item is selected due to defaultValues
+			expect( currentSelectedItem ).toHaveTextContent(
+				`${ defaultValues.length } items selected`
+			);
+
+			await user.click( currentSelectedItem );
+
+			expect( screen.getByRole( 'listbox' ) ).toHaveAttribute(
+				'aria-multiselectable'
+			);
+
+			// ensure defaultValues are selected in list of items
+			defaultValues.forEach( ( value ) =>
+				expect(
+					screen.getByRole( 'option', {
+						name: value,
+						selected: true,
+					} )
+				).toBeVisible()
+			);
+
+			// name of next selection
+			const nextSelectionName = 'rose blush';
+
+			// element for next selection
+			const nextSelection = screen.getByRole( 'option', {
+				name: nextSelectionName,
+			} );
+
+			// click next selection to add another item to current selection
+			await user.click( nextSelection );
+
+			// updated array containing defaultValues + the item just selected
+			const updatedSelection = defaultValues.concat( nextSelectionName );
+
+			expect( onChangeMock ).toHaveBeenCalledWith( updatedSelection );
+
+			expect( nextSelection ).toHaveAttribute( 'aria-selected' );
+
+			// expect increased array length for current selection
+			expect( currentSelectedItem ).toHaveTextContent(
+				`${ updatedSelection.length } items selected`
+			);
+		} );
+
+		it( 'Should be able to deselect items when provided an array', async () => {
+			const user = userEvent.setup();
+
+			// initial selection as defaultValue
+			const defaultValues = [
+				'aurora borealis green',
+				'incandescent glow',
+				'key lime green',
+				'rose blush',
+				'ultraviolet morning light',
+			];
+
+			render(
+				<Component defaultValue={ defaultValues } label="Multi-select">
+					{ defaultValues.map( ( item ) => (
+						<CustomSelectItem key={ item } value={ item }>
+							{ item }
+						</CustomSelectItem>
+					) ) }
+				</Component>
+			);
+
+			const currentSelectedItem = screen.getByRole( 'combobox', {
+				expanded: false,
+			} );
+
+			await user.click( currentSelectedItem );
+
+			// Array containing items to deselect
+			const nextSelection = [
+				'aurora borealis green',
+				'rose blush',
+				'incandescent glow',
+			];
+
+			// Deselect some items by clicking them to ensure that changes
+			// are reflected correctly
+			await Promise.all(
+				nextSelection.map( async ( value ) => {
+					await user.click(
+						screen.getByRole( 'option', { name: value } )
+					);
+					expect(
+						screen.getByRole( 'option', {
+							name: value,
+							selected: false,
+						} )
+					).toBeVisible();
+				} )
+			);
+
+			// expect different array length from defaultValues due to deselecting items
+			expect( currentSelectedItem ).toHaveTextContent(
+				`${
+					defaultValues.length - nextSelection.length
+				} items selected`
+			);
+		} );
+	} );
+
+	it( 'Should allow rendering a custom value when using `renderSelectedValue`', async () => {
+		const user = userEvent.setup();
+
+		const renderValue = ( value: string | string[] ) => {
+			return <img src={ `${ value }.jpg` } alt={ value as string } />;
+		};
+
+		render(
+			<Component label="Rendered" renderSelectedValue={ renderValue }>
+				<CustomSelectItem value="april-29">
+					{ renderValue( 'april-29' ) }
+				</CustomSelectItem>
+				<CustomSelectItem value="july-9">
+					{ renderValue( 'july-9' ) }
+				</CustomSelectItem>
+			</Component>
+		);
+
+		const currentSelectedItem = screen.getByRole( 'combobox', {
+			expanded: false,
+		} );
+
+		expect( currentSelectedItem ).toBeVisible();
+
+		// expect that the initial selection renders an image
+		expect( currentSelectedItem ).toContainElement(
+			screen.getByRole( 'img', { name: 'april-29' } )
+		);
+
+		expect(
+			screen.queryByRole( 'img', { name: 'july-9' } )
+		).not.toBeInTheDocument();
+
+		await user.click( currentSelectedItem );
+
+		// expect that the other image is only visible after opening popover with options
+		expect( screen.getByRole( 'img', { name: 'july-9' } ) ).toBeVisible();
+		expect(
+			screen.getByRole( 'option', { name: 'july-9' } )
+		).toBeVisible();
+	} );
+} );