diff --git a/src/components/layout/sidebar-navigation/SidebarNavigation.tsx b/src/components/layout/sidebar-navigation/SidebarNavigation.tsx
index 3da4c224..1c54a571 100644
--- a/src/components/layout/sidebar-navigation/SidebarNavigation.tsx
+++ b/src/components/layout/sidebar-navigation/SidebarNavigation.tsx
@@ -89,7 +89,6 @@ const SidebarNavigationWrapper = styled.nav`
   box-sizing: content-box;
   overflow: hidden;
 
-  padding-top: ${cssVar('dimension-space-100')};
   border-right: ${cssVar('border-width-default')} solid ${cssVar('color-border-weak')};
   background-color: ${cssVar('color-surface-default')};
 
diff --git a/src/components/layout/sidebar-navigation/SidebarNavigationAccordionItem.tsx b/src/components/layout/sidebar-navigation/SidebarNavigationAccordionItem.tsx
index d754f7c4..8290497f 100644
--- a/src/components/layout/sidebar-navigation/SidebarNavigationAccordionItem.tsx
+++ b/src/components/layout/sidebar-navigation/SidebarNavigationAccordionItem.tsx
@@ -65,6 +65,10 @@ export interface SidebarNavigationAccordionItemProps {
    * The onOpen callback is called when the accordion is opened.
    */
   onOpen?: VoidFunction;
+  /**
+   * Whether the accordion is open by default. Defaults to false.
+   */
+  isDefaultOpen?: boolean;
   /**
    * When true, scrolls the last child item into view when the accordion opens.
    * Useful when the accordion is near the bottom of a scrollable container.
@@ -87,6 +91,7 @@ export const SidebarNavigationAccordionItem = forwardRef<
 >((props, ref) => {
   const {
     children,
+    isDefaultOpen = false,
     disableTooltip = false,
     Icon,
     label,
@@ -97,7 +102,7 @@ export const SidebarNavigationAccordionItem = forwardRef<
     ...htmlProps
   } = props;
 
-  const [open, setOpen] = useState(false);
+  const [open, setOpen] = useState(isDefaultOpen);
   const panelRef = useRef<HTMLElement>(null);
 
   useEffect(() => {
diff --git a/src/components/layout/sidebar-navigation/SidebarNavigationHeader.tsx b/src/components/layout/sidebar-navigation/SidebarNavigationHeader.tsx
index 3f714db0..58c20a0a 100644
--- a/src/components/layout/sidebar-navigation/SidebarNavigationHeader.tsx
+++ b/src/components/layout/sidebar-navigation/SidebarNavigationHeader.tsx
@@ -56,47 +56,56 @@ export const SidebarNavigationHeader = forwardRef<HTMLButtonElement, SidebarNavi
     const [isOverflow] = useIsOverflow(labelRef, [name]);
 
     return (
-      <Tooltip content={isOverflow && isInteractive ? name : undefined} side={TooltipSide.Right}>
-        <HeaderContainer as={isInteractive ? 'button' : 'div'} ref={ref} {...radixProps}>
-          <MainContent>
-            {avatar && <AvatarWrapper>{avatar}</AvatarWrapper>}
-            <TextContent>
-              <Text isHighlighted ref={labelRef}>
-                {name}
-              </Text>
-              {qualifier && (
-                <Text isSubtle size="small">
-                  {qualifier}
+      <HeaderWrapper>
+        <Tooltip content={isOverflow && isInteractive ? name : undefined} side={TooltipSide.Right}>
+          <HeaderContainer as={isInteractive ? 'button' : 'div'} ref={ref} {...radixProps}>
+            <MainContent>
+              {avatar && <AvatarWrapper>{avatar}</AvatarWrapper>}
+              <TextContent>
+                <Text isHighlighted ref={labelRef}>
+                  {name}
                 </Text>
-              )}
-            </TextContent>
-          </MainContent>
-          {isInteractive && <IconExpandAll />}
-        </HeaderContainer>
-      </Tooltip>
+                {qualifier && (
+                  <Text isSubtle size="small">
+                    {qualifier}
+                  </Text>
+                )}
+              </TextContent>
+            </MainContent>
+            {isInteractive && <IconExpandAll />}
+          </HeaderContainer>
+        </Tooltip>
+      </HeaderWrapper>
     );
   },
 );
 SidebarNavigationHeader.displayName = 'SidebarNavigationHeader';
 
+const HeaderWrapper = styled.div`
+  padding: ${cssVar('dimension-space-100')};
+  display: flex;
+  border-bottom: ${cssVar('border-width-default')} solid ${cssVar('color-border-weak')};
+
+  [data-sidebar-docked='false'] nav:not(:hover, :focus-within) & {
+    padding-left: ${cssVar('dimension-space-50')};
+    padding-right: ${cssVar('dimension-space-50')};
+  }
+`;
+HeaderWrapper.displayName = 'HeaderWrapper';
+
 const HeaderContainer = styled.button`
   all: unset;
 
   display: flex;
   align-items: center;
   justify-content: space-between;
-  flex-shrink: 0;
+  flex: 1 0 0;
 
   gap: ${cssVar('dimension-space-100')};
   padding: ${cssVar('dimension-space-100')};
-  margin: ${cssVar('dimension-space-100')};
 
   overflow: hidden;
 
-  [data-sidebar-docked='false'] nav:not(:hover, :focus-within) & {
-    margin: ${cssVar('dimension-space-100')} ${cssVar('dimension-space-50')};
-  }
-
   /* If it is interactive, we want mouse interactivity */
   :is(button) {
     border-radius: ${cssVar('border-radius-400')};
@@ -129,7 +138,7 @@ const MainContent = styled.div`
   display: flex;
   align-items: center;
   gap: ${cssVar('dimension-space-100')};
-  min-width: ${cssVar('dimension-width-300')};
+  min-width: ${cssVar('dimension-width-400')};
 `;
 MainContent.displayName = 'MainContent';
 
diff --git a/src/components/layout/sidebar-navigation/__tests__/SidebarNavigationAccordionItem-test.tsx b/src/components/layout/sidebar-navigation/__tests__/SidebarNavigationAccordionItem-test.tsx
index c495ac04..b4065c7c 100644
--- a/src/components/layout/sidebar-navigation/__tests__/SidebarNavigationAccordionItem-test.tsx
+++ b/src/components/layout/sidebar-navigation/__tests__/SidebarNavigationAccordionItem-test.tsx
@@ -53,6 +53,13 @@ it('should expand hidden elements when clicked', async () => {
   expect(onClose).toHaveBeenCalled();
 });
 
+it('should render the accordion open when defaultOpen is true', () => {
+  setupSidebarNavigationAccordionItem({ isDefaultOpen: true });
+
+  checkAccordionPanelVisibility(true);
+  expect(screen.getAllByRole('link')).toHaveLength(2);
+});
+
 it("shouldn't have any a11y violation", async () => {
   const { container, user } = setupSidebarNavigationAccordionItem({ Icon: IconBranch });
   await expect(container).toHaveNoA11yViolations();
diff --git a/stories/layout/sidebar-navigation/SidebarNavigationAccordionItem-stories.tsx b/stories/layout/sidebar-navigation/SidebarNavigationAccordionItem-stories.tsx
index 10f556b9..fe064e9b 100644
--- a/stories/layout/sidebar-navigation/SidebarNavigationAccordionItem-stories.tsx
+++ b/stories/layout/sidebar-navigation/SidebarNavigationAccordionItem-stories.tsx
@@ -20,12 +20,41 @@
 
 /* eslint-disable no-console */
 import type { Meta, StoryObj } from '@storybook/react-vite';
-import { Badge, IconBranch, Layout } from '../../../src';
+import { Badge, cssVar, IconBranch, Layout } from '../../../src';
 import { basicWrapperDecorator } from '../../helpers/BasicWrapper';
 
-const meta: Meta = {
+const baseAccordionChildren = (
+  <>
+    <Layout.SidebarNavigation.Item Icon={IconBranch} to="/1">
+      Item 1
+    </Layout.SidebarNavigation.Item>
+
+    <Layout.SidebarNavigation.Item Icon={IconBranch} to="/2">
+      Item 2
+    </Layout.SidebarNavigation.Item>
+  </>
+);
+
+const dockedSidebarAccordionChildren = (
+  <>
+    <Layout.SidebarNavigation.Item Icon={IconBranch} disableIconWhenSidebarOpen to="/1">
+      Icon hidden while sidebar is open
+    </Layout.SidebarNavigation.Item>
+
+    <Layout.SidebarNavigation.Item Icon={IconBranch} to="/2">
+      Icon stays visible while sidebar is open
+    </Layout.SidebarNavigation.Item>
+  </>
+);
+
+const meta: Meta<typeof Layout.SidebarNavigation.AccordionItem> = {
   title: 'Echoes/Layout/SidebarNavigation/AccordionItem',
   component: Layout.SidebarNavigation.AccordionItem,
+  argTypes: {
+    isDefaultOpen: {
+      control: { type: 'boolean' },
+    },
+  },
   decorators: [
     (Story) => (
       <Layout.SidebarNavigation.Body>
@@ -34,6 +63,13 @@ const meta: Meta = {
     ),
     basicWrapperDecorator,
   ],
+  render: ({ isDefaultOpen = false, ...args }) => (
+    <Layout.SidebarNavigation.AccordionItem
+      isDefaultOpen={isDefaultOpen}
+      key={`accordion-default-open-${isDefaultOpen.toString()}`}
+      {...args}
+    />
+  ),
 };
 
 export default meta;
@@ -43,16 +79,8 @@ type Story = StoryObj<typeof Layout.SidebarNavigation.AccordionItem>;
 export const base: Story = {
   args: {
     Icon: IconBranch,
-    children: (
-      <>
-        <Layout.SidebarNavigation.Item Icon={IconBranch} disableIconWhenSidebarOpen to="/1">
-          Item 1
-        </Layout.SidebarNavigation.Item>
-        <Layout.SidebarNavigation.Item Icon={IconBranch} disableIconWhenSidebarOpen to="/2">
-          Item 2
-        </Layout.SidebarNavigation.Item>
-      </>
-    ),
+    children: baseAccordionChildren,
+    isDefaultOpen: false,
     label: 'Accordion',
   },
 };
@@ -60,16 +88,8 @@ export const base: Story = {
 export const suffixed: Story = {
   args: {
     Icon: IconBranch,
-    children: (
-      <>
-        <Layout.SidebarNavigation.Item Icon={IconBranch} disableIconWhenSidebarOpen to="/1">
-          Item 1
-        </Layout.SidebarNavigation.Item>
-        <Layout.SidebarNavigation.Item Icon={IconBranch} disableIconWhenSidebarOpen to="/2">
-          Item 2
-        </Layout.SidebarNavigation.Item>
-      </>
-    ),
+    children: baseAccordionChildren,
+    isDefaultOpen: false,
     label: 'Accordion',
     suffix: (
       <Badge isHighContrast variety="highlight">
@@ -79,6 +99,35 @@ export const suffixed: Story = {
   },
 };
 
+export const withDefaultOpen: Story = {
+  args: {
+    Icon: IconBranch,
+    children: baseAccordionChildren,
+    isDefaultOpen: true,
+    label: 'Accordion',
+  },
+};
+
+export const withDisableIconWhenSidebarOpen: Story = {
+  args: {
+    Icon: IconBranch,
+    isDefaultOpen: true,
+    label: 'Accordion',
+  },
+  render: ({ isDefaultOpen = true, ...args }) => (
+    <div
+      data-sidebar-docked="true"
+      style={{ width: cssVar('layout-sidebar-navigation-sizes-width-open') }}>
+      <Layout.SidebarNavigation.AccordionItem
+        isDefaultOpen={isDefaultOpen}
+        key={`accordion-disable-icon-when-sidebar-open-${isDefaultOpen.toString()}`}
+        {...args}>
+        {dockedSidebarAccordionChildren}
+      </Layout.SidebarNavigation.AccordionItem>
+    </div>
+  ),
+};
+
 const fourNavItems = Array.from({ length: 4 }, (_, i) => (
   <Layout.SidebarNavigation.Item Icon={IconBranch} key={i} to={`/item-${i}`}>
     Item {`${i + 1}`}