diff --git a/packages/components/src/tab-panel/test/index.tsx b/packages/components/src/tab-panel/test/index.tsx
index d2e4bd07e25a8a..a7899dd821fdde 100644
--- a/packages/components/src/tab-panel/test/index.tsx
+++ b/packages/components/src/tab-panel/test/index.tsx
@@ -27,6 +27,8 @@ const TABS = [
 	},
 ];
 
+const getSelectedTab = () => screen.getByRole( 'tab', { selected: true } );
+
 let originalGetClientRects: () => DOMRectList;
 
 describe.each( [
@@ -51,4 +53,418 @@ describe.each( [
 	afterAll( () => {
 		window.HTMLElement.prototype.getClientRects = originalGetClientRects;
 	} );
+
+	describe( 'Without `initialTabName`', () => {
+		it( 'should render first tab', async () => {
+			const panelRenderFunction = jest.fn();
+
+			render(
+				<Component tabs={ TABS } children={ panelRenderFunction } />
+			);
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Alpha' );
+			expect(
+				screen.getByRole( 'tabpanel', { name: 'Alpha' } )
+			).toBeInTheDocument();
+			expect( panelRenderFunction ).toHaveBeenLastCalledWith( TABS[ 0 ] );
+		} );
+
+		it( 'should fall back to first enabled tab if the active tab is removed', async () => {
+			const mockOnSelect = jest.fn();
+			const { rerender } = render(
+				<Component
+					tabs={ TABS }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			rerender(
+				<Component
+					tabs={ TABS.slice( 1 ) /* remove alpha */ }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+			expect( getSelectedTab() ).toHaveTextContent( 'Beta' );
+		} );
+	} );
+
+	describe( 'With `initialTabName`', () => {
+		it( 'should render the tab set by initialTabName prop', () => {
+			render(
+				<Component
+					initialTabName="beta"
+					tabs={ TABS }
+					children={ () => undefined }
+				/>
+			);
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Beta' );
+		} );
+
+		it( 'should not render a tab when initialTabName does not exist', () => {
+			render(
+				<Component
+					initialTabName="does-not-exist"
+					tabs={ TABS }
+					children={ () => undefined }
+				/>
+			);
+
+			// No tab should be rendered i.e. it doesn't fall back to first tab.
+			expect(
+				screen.queryByRole( 'tab', { selected: true } )
+			).not.toBeInTheDocument();
+		} );
+
+		it( 'should not change tabs when initialTabName is changed', () => {
+			const { rerender } = render(
+				<Component
+					initialTabName="beta"
+					tabs={ TABS }
+					children={ () => undefined }
+				/>
+			);
+
+			rerender(
+				<Component
+					initialTabName="alpha"
+					tabs={ TABS }
+					children={ () => undefined }
+				/>
+			);
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Beta' );
+		} );
+
+		it( 'should fall back to initial tab if active tab is removed', async () => {
+			const user = userEvent.setup();
+			const mockOnSelect = jest.fn();
+			const { rerender } = render(
+				<Component
+					initialTabName="gamma"
+					tabs={ TABS }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			await user.click( screen.getByRole( 'tab', { name: 'Alpha' } ) );
+
+			rerender(
+				<Component
+					initialTabName="gamma"
+					tabs={ TABS.slice( 1 ) /* remove alpha */ }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Gamma' );
+		} );
+
+		it( 'waits for the tab with the `initialTabName` to be present in the `tabs` array before selecting it', () => {
+			const mockOnSelect = jest.fn();
+			const { rerender } = render(
+				<Component
+					initialTabName="delta"
+					tabs={ TABS }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			// There should be no selected tab yet.
+			expect(
+				screen.queryByRole( 'tab', { selected: true } )
+			).not.toBeInTheDocument();
+
+			rerender(
+				<Component
+					initialTabName="delta"
+					tabs={ [
+						{
+							name: 'delta',
+							title: 'Delta',
+							className: 'delta-class',
+						},
+						...TABS,
+					] }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Delta' );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'delta' );
+		} );
+	} );
+
+	describe( 'Disabled Tab', () => {
+		it( 'should disable the tab when `disabled` is `true`', async () => {
+			const user = userEvent.setup();
+			const mockOnSelect = jest.fn();
+
+			render(
+				<Component
+					tabs={ [
+						...TABS,
+						{
+							name: 'delta',
+							title: 'Delta',
+							className: 'delta-class',
+							disabled: true,
+						},
+					] }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			expect(
+				screen.getByRole( 'tab', { name: 'Delta' } )
+			).toHaveAttribute( 'aria-disabled', 'true' );
+
+			// onSelect gets called on the initial render.
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 1 );
+
+			// onSelect should not be called since the disabled tab is
+			// highlighted, but not selected.
+			await user.keyboard( '[ArrowLeft]' );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 1 );
+		} );
+
+		it( 'should select first enabled tab when initial tab is disabled', () => {
+			const mockOnSelect = jest.fn();
+
+			render(
+				<Component
+					tabs={ TABS.map( ( tab ) => {
+						if ( tab.name === 'gamma' ) {
+							return tab;
+						}
+						return { ...tab, disabled: true };
+					} ) }
+					initialTabName="beta"
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			// As alpha (first tab), and beta (the initial tab), are both
+			// disabled the first enabled tab should be gamma.
+			expect(
+				screen.queryByRole( 'tab', { selected: true } )
+			).toHaveTextContent( 'Gamma' );
+		} );
+
+		it( 'should select the first enabled tab when the selected tab becomes disabled', () => {
+			const mockOnSelect = jest.fn();
+			const { rerender } = render(
+				<Component
+					tabs={ TABS }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Alpha' );
+
+			rerender(
+				<Component
+					tabs={ TABS.map( ( tab ) => {
+						if ( tab.name === 'alpha' ) {
+							return { ...tab, disabled: true };
+						}
+						return tab;
+					} ) }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Beta' );
+		} );
+	} );
+
+	describe( 'Tab Activation', () => {
+		it( 'should render a tabpanel, and clicking should change tabs', async () => {
+			const user = userEvent.setup();
+			const panelRenderFunction = jest.fn();
+			const mockOnSelect = jest.fn();
+
+			render(
+				<Component
+					tabs={ TABS }
+					children={ panelRenderFunction }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Alpha' );
+			expect(
+				screen.getByRole( 'tabpanel', { name: 'Alpha' } )
+			).toBeInTheDocument();
+			expect( panelRenderFunction ).toHaveBeenLastCalledWith( TABS[ 0 ] );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'alpha' );
+
+			await user.click( screen.getByRole( 'tab', { name: 'Beta' } ) );
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Beta' );
+			expect(
+				screen.getByRole( 'tabpanel', { name: 'Beta' } )
+			).toBeInTheDocument();
+			expect( panelRenderFunction ).toHaveBeenLastCalledWith( TABS[ 1 ] );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'beta' );
+
+			await user.click( screen.getByRole( 'tab', { name: 'Alpha' } ) );
+
+			expect( getSelectedTab() ).toHaveTextContent( 'Alpha' );
+			expect(
+				screen.getByRole( 'tabpanel', { name: 'Alpha' } )
+			).toBeInTheDocument();
+			expect( panelRenderFunction ).toHaveBeenLastCalledWith( TABS[ 0 ] );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'alpha' );
+		} );
+
+		it( 'defaults to automatic tab activation', async () => {
+			const user = userEvent.setup();
+			const mockOnSelect = jest.fn();
+
+			render(
+				<Component
+					tabs={ TABS }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+				/>
+			);
+
+			// onSelect gets called on the initial render.
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 1 );
+
+			// Click on Alpha. Make sure alpha is selected.
+			await user.click( screen.getByRole( 'tab', { name: 'Alpha' } ) );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 2 );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'alpha' );
+
+			// Navigate forward with arrow keys and make sure the Beta tab is
+			// selected automatically.
+			await user.keyboard( '[ArrowRight]' );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 3 );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'beta' );
+
+			// Navigate forward with arrow keys. Make sure gamma (last tab) is
+			// selected automatically.
+			await user.keyboard( '[ArrowRight]' );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 4 );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'gamma' );
+
+			// Navigate forward with arrow keys. Make sure Alpha (first tab) is
+			// selected automatically.
+			await user.keyboard( '[ArrowRight]' );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 5 );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'alpha' );
+
+			// Navigate backwards with arrow keys. Make sure Gamma (last tab) is
+			// selected automatically.
+			await user.keyboard( '[ArrowLeft]' );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 6 );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'gamma' );
+		} );
+
+		it( 'switches to manual tab activation when the `selectOnMove` prop is set to `false`', async () => {
+			const user = userEvent.setup();
+			const mockOnSelect = jest.fn();
+
+			render(
+				<Component
+					tabs={ TABS }
+					children={ () => undefined }
+					onSelect={ mockOnSelect }
+					selectOnMove={ false }
+				/>
+			);
+
+			// onSelect gets called on the initial render.
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 1 );
+
+			// Click on Alpha and make sure it is selected.
+			await user.click( screen.getByRole( 'tab', { name: 'Alpha' } ) );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 2 );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'alpha' );
+
+			// Navigate forward with arrow keys. Make sure Beta is focused, but
+			// that the tab selection happens only when pressing the spacebar
+			// or enter key.
+			await user.keyboard( '[ArrowRight]' );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 2 );
+			expect( screen.getByRole( 'tab', { name: 'Beta' } ) ).toHaveFocus();
+
+			await user.keyboard( '[Enter]' );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 3 );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'beta' );
+
+			// Navigate forward with arrow keys. Make sure Gamma (last tab) is
+			// focused, but that tab selection happens only when pressing the
+			// spacebar or enter key.
+			await user.keyboard( '[ArrowRight]' );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 3 );
+			expect(
+				screen.getByRole( 'tab', { name: 'Gamma' } )
+			).toHaveFocus();
+
+			await user.keyboard( '[Space]' );
+			expect( mockOnSelect ).toHaveBeenCalledTimes( 4 );
+			expect( mockOnSelect ).toHaveBeenLastCalledWith( 'gamma' );
+
+			// No need to test the "wrap-around" behaviour, as it is being
+			// tested in the "automatic tab activation" test above.
+		} );
+	} );
+
+	describe( 'Tab Attributes', () => {
+		it( "should apply the tab's `className` to the tab button", () => {
+			render( <Component tabs={ TABS } children={ () => undefined } /> );
+
+			expect( screen.getByRole( 'tab', { name: 'Alpha' } ) ).toHaveClass(
+				'alpha-class'
+			);
+			expect( screen.getByRole( 'tab', { name: 'Beta' } ) ).toHaveClass(
+				'beta-class'
+			);
+			expect( screen.getByRole( 'tab', { name: 'Gamma' } ) ).toHaveClass(
+				'gamma-class'
+			);
+		} );
+
+		it( 'should apply the `activeClass` to the selected tab', async () => {
+			const user = userEvent.setup();
+			const activeClass = 'my-active-tab';
+
+			render(
+				<Component
+					activeClass={ activeClass }
+					tabs={ TABS }
+					children={ () => undefined }
+				/>
+			);
+
+			expect( getSelectedTab() ).toHaveClass( activeClass );
+			screen
+				.getAllByRole( 'tab', { selected: false } )
+				.forEach( ( unselectedTab ) => {
+					expect( unselectedTab ).not.toHaveClass( activeClass );
+				} );
+
+			await user.click( screen.getByRole( 'tab', { name: 'Beta' } ) );
+
+			expect( getSelectedTab() ).toHaveClass( activeClass );
+			screen
+				.getAllByRole( 'tab', { selected: false } )
+				.forEach( ( unselectedTab ) => {
+					expect( unselectedTab ).not.toHaveClass( activeClass );
+				} );
+		} );
+	} );
 } );