diff --git a/.changeset/afraid-rats-invent.md b/.changeset/afraid-rats-invent.md
new file mode 100644
index 0000000000..0caa57d81c
--- /dev/null
+++ b/.changeset/afraid-rats-invent.md
@@ -0,0 +1,14 @@
+---
+'@backstage/ui': patch
+---
+
+Added a new `FullPage` component that fills the remaining viewport height below the `Header`.
+
+```tsx
+<Header title="My Plugin" tabs={tabs} />
+<FullPage>
+  {/* content fills remaining height */}
+</FullPage>
+```
+
+**Affected components:** FullPage
diff --git a/packages/ui/report.api.md b/packages/ui/report.api.md
index 4d09023b69..b25b3c9b27 100644
--- a/packages/ui/report.api.md
+++ b/packages/ui/report.api.md
@@ -979,6 +979,21 @@ export interface FlexProps extends SpaceProps {
 // @public (undocumented)
 export type FlexWrap = 'wrap' | 'nowrap' | 'wrap-reverse';
 
+// @public
+export const FullPage: ForwardRefExoticComponent<
+  FullPageProps & RefAttributes<HTMLElement>
+>;
+
+// @public
+export const FullPageDefinition: {
+  readonly classNames: {
+    readonly root: 'bui-FullPage';
+  };
+};
+
+// @public
+export interface FullPageProps extends React.ComponentPropsWithoutRef<'main'> {}
+
 // @public (undocumented)
 export const Grid: {
   Root: ForwardRefExoticComponent<GridProps & RefAttributes<HTMLDivElement>>;
@@ -1082,6 +1097,7 @@ export const Header: (props: HeaderProps) => JSX_2.Element;
 // @public
 export const HeaderDefinition: {
   readonly classNames: {
+    readonly root: 'bui-Header';
     readonly toolbar: 'bui-HeaderToolbar';
     readonly toolbarWrapper: 'bui-HeaderToolbarWrapper';
     readonly toolbarContent: 'bui-HeaderToolbarContent';
diff --git a/packages/ui/src/components/Header/Header.module.css b/packages/ui/src/components/Header/Header.module.css
index ba014cfd48..4cd94d30ea 100644
--- a/packages/ui/src/components/Header/Header.module.css
+++ b/packages/ui/src/components/Header/Header.module.css
@@ -88,7 +88,6 @@
   }
 
   .bui-HeaderTabsWrapper {
-    margin-bottom: var(--bui-space-4);
     padding-inline: var(--bui-space-3);
     border-bottom: 1px solid var(--bui-border);
     background-color: var(--bui-bg-neutral-1);