diff --git a/ui/components/app/perps/order-book/order-book-config-modal.tsx b/ui/components/app/perps/order-book/order-book-config-modal.tsx
index 6620020d59fe..2efda0eac07e 100644
--- a/ui/components/app/perps/order-book/order-book-config-modal.tsx
+++ b/ui/components/app/perps/order-book/order-book-config-modal.tsx
@@ -44,9 +44,10 @@ import type {
 
 const PILL_BASE_CLASS =
   'flex items-center justify-center rounded-full py-3 px-4 cursor-pointer transition-colors duration-150 border';
-const PILL_SELECTED_CLASS = 'bg-transparent border-muted';
+
+const PILL_SELECTED_CLASS = 'bg-muted border-transparent';
 const PILL_UNSELECTED_CLASS =
-  'bg-muted border-transparent hover:bg-muted-hover';
+  'bg-transparent border-muted hover:bg-muted-hover';
 
 type PillProps = {
   label: string;
diff --git a/ui/pages/perps/perps-order-entry-page.test.tsx b/ui/pages/perps/perps-order-entry-page.test.tsx
index 533b368f685e..9e9fcaef12f7 100644
--- a/ui/pages/perps/perps-order-entry-page.test.tsx
+++ b/ui/pages/perps/perps-order-entry-page.test.tsx
@@ -712,6 +712,43 @@ describe('PerpsOrderEntryPage', () => {
       expect(divider).toHaveAttribute('aria-valuenow', '33');
     });
 
+    it('mounts the order book already open when the persisted preference is expanded', () => {
+      const state = createMockState();
+      const store = mockStore({
+        ...state,
+        metamask: {
+          ...state.metamask,
+          proLayoutPreferences: { orderBookExpanded: true },
+        },
+      });
+      renderWithProvider(<PerpsOrderEntryPage />, store);
+
+      expect(screen.getByTestId('perps-order-book-toggle')).toHaveAttribute(
+        'aria-pressed',
+        'true',
+      );
+      expect(screen.getByTestId('perps-order-book')).toBeInTheDocument();
+    });
+
+    it('persists the open state when the order book is toggled', () => {
+      const store = mockStore(createMockState());
+      renderWithProvider(<PerpsOrderEntryPage />, store);
+
+      const toggle = screen.getByTestId('perps-order-book-toggle');
+
+      fireEvent.click(toggle);
+      expect(mockSubmitRequestToBackground).toHaveBeenCalledWith(
+        'perpsSetProLayoutPreferences',
+        [{ orderBookExpanded: true }],
+      );
+
+      fireEvent.click(toggle);
+      expect(mockSubmitRequestToBackground).toHaveBeenCalledWith(
+        'perpsSetProLayoutPreferences',
+        [{ orderBookExpanded: false }],
+      );
+    });
+
     it('resizes the split within bounds using the keyboard', () => {
       const store = mockStore(createMockStateWithOrderBookPosition('right'));
       renderWithProvider(<PerpsOrderEntryPage />, store);
diff --git a/ui/pages/perps/perps-order-entry-page.tsx b/ui/pages/perps/perps-order-entry-page.tsx
index 7681588eaf53..684353aca8c7 100644
--- a/ui/pages/perps/perps-order-entry-page.tsx
+++ b/ui/pages/perps/perps-order-entry-page.tsx
@@ -72,6 +72,7 @@ import {
   selectPerpsIsTestnet,
   selectPerpsActiveProvider,
   selectOrderBookPosition,
+  selectOrderBookExpanded,
 } from '../../selectors/perps-controller';
 import {
   CandlePeriod,
@@ -301,7 +302,10 @@ const PerpsOrderEntryPage = () => {
   const { buildTrackingData, buildTpslTrackingData, setFlowAttribution } =
     usePerpsAttribution();
   const [isGeoBlockModalOpen, setIsGeoBlockModalOpen] = useState(false);
-  const [isOrderBookOpen, setIsOrderBookOpen] = useState(false);
+  const persistedOrderBookExpanded = useSelector(selectOrderBookExpanded);
+  const [isOrderBookOpen, setIsOrderBookOpen] = useState(
+    persistedOrderBookExpanded,
+  );
   const [orderBookWidthPct, setOrderBookWidthPct] = useState(
     ORDER_BOOK_DEFAULT_WIDTH_PCT,
   );
@@ -1447,6 +1451,11 @@ const PerpsOrderEntryPage = () => {
   const handleToggleOrderBook = useCallback(() => {
     const next = !isOrderBookOpen;
     setIsOrderBookOpen(next);
+    submitRequestToBackground('perpsSetProLayoutPreferences', [
+      { orderBookExpanded: next },
+    ]).catch((error) =>
+      console.error('Failed to persist order book open state', error),
+    );
     // Tracking is a side effect and must run outside the state updater (updaters
     // must be pure and may be invoked more than once). Specific open/close values
     // keep dark-launch open-rate measurable (generic TAP cannot).
diff --git a/ui/selectors/perps-controller.test.ts b/ui/selectors/perps-controller.test.ts
index 1f7684302602..3f559c370bf8 100644
--- a/ui/selectors/perps-controller.test.ts
+++ b/ui/selectors/perps-controller.test.ts
@@ -31,6 +31,7 @@ import {
   selectPerpsShouldShowDepositToast,
   selectProLayoutPreferences,
   selectOrderBookPosition,
+  selectOrderBookExpanded,
 } from './perps-controller';
 
 function buildState(overrides: Record<string, unknown> = {}) {
@@ -855,4 +856,21 @@ describe('perps-controller selectors', () => {
       ).toBe('left');
     });
   });
+
+  describe('selectOrderBookExpanded', () => {
+    it('returns the persisted open state', () => {
+      expect(
+        selectOrderBookExpanded(
+          buildState({ proLayoutPreferences: { orderBookExpanded: true } }),
+        ),
+      ).toBe(true);
+    });
+
+    it('defaults to closed', () => {
+      expect(selectOrderBookExpanded(buildState())).toBe(false);
+      expect(
+        selectOrderBookExpanded(buildState({ proLayoutPreferences: {} })),
+      ).toBe(false);
+    });
+  });
 });
diff --git a/ui/selectors/perps-controller.ts b/ui/selectors/perps-controller.ts
index aa07ca8f1081..9e616c421c95 100644
--- a/ui/selectors/perps-controller.ts
+++ b/ui/selectors/perps-controller.ts
@@ -239,5 +239,17 @@ export const selectOrderBookPosition = (state: PerpsState) =>
   state.metamask.proLayoutPreferences?.orderBookPosition ??
   DEFAULT_PRO_LAYOUT_PREFERENCES.orderBookPosition;
 
+/**
+ * Whether the order book panel was left open. Global across markets (the
+ * preference object is flat, not per-market), so the panel opens in the same
+ * state on every symbol.
+ *
+ * @param state - Perps controller state.
+ * @returns True when the panel should start open.
+ */
+export const selectOrderBookExpanded = (state: PerpsState) =>
+  state.metamask.proLayoutPreferences?.orderBookExpanded ??
+  DEFAULT_PRO_LAYOUT_PREFERENCES.orderBookExpanded;
+
 export const selectPerpsTradeConfigurations = (state: PerpsState) =>
   state.metamask.tradeConfigurations ?? EMPTY_TRADE_CONFIGURATIONS;