diff --git a/packages/react/src/select/trigger/SelectTrigger.test.tsx b/packages/react/src/select/trigger/SelectTrigger.test.tsx
index 43ac94c4d7a..6f62ce3728c 100644
--- a/packages/react/src/select/trigger/SelectTrigger.test.tsx
+++ b/packages/react/src/select/trigger/SelectTrigger.test.tsx
@@ -145,6 +145,47 @@ describe('<Select.Trigger />', () => {
       expect(trigger).toHaveAttribute('aria-expanded', 'true');
     });
 
+    it('does not close on a later mouseup when the opening click already ended', async () => {
+      const onOpenChange = vi.fn();
+      await render(
+        <Select.Root onOpenChange={onOpenChange}>
+          <Select.Trigger data-testid="trigger">
+            <Select.Value />
+          </Select.Trigger>
+          <Select.Portal>
+            <Select.Positioner alignItemWithTrigger={false}>
+              <Select.Popup>
+                <Select.Item value="a">a</Select.Item>
+              </Select.Popup>
+            </Select.Positioner>
+          </Select.Portal>
+        </Select.Root>,
+      );
+
+      const trigger = screen.getByTestId('trigger');
+      trigger.getBoundingClientRect = () =>
+        DOMRect.fromRect({ x: 100, y: 100, width: 100, height: 40 });
+
+      fireEvent.pointerDown(trigger, { pointerType: 'mouse', button: 0 });
+      fireEvent.mouseDown(trigger, { button: 0 });
+      fireEvent.mouseUp(trigger, { button: 0, clientX: 120, clientY: 120 });
+
+      await act(async () => {
+        await wait(20);
+      });
+
+      expect(trigger).toHaveAttribute('aria-expanded', 'true');
+      onOpenChange.mockClear();
+
+      fireEvent.mouseUp(document.body, { button: 0, clientX: 94, clientY: 120 });
+      await act(async () => {
+        await wait(20);
+      });
+
+      expect(trigger).toHaveAttribute('aria-expanded', 'true');
+      expect(onOpenChange).not.toHaveBeenCalled();
+    });
+
     it('closes the popup when the press is dragged off the trigger and released', async () => {
       const trigger = await pressTrigger();
 
diff --git a/packages/react/src/select/trigger/SelectTrigger.tsx b/packages/react/src/select/trigger/SelectTrigger.tsx
index c10336d03ac..679dfc43a5e 100644
--- a/packages/react/src/select/trigger/SelectTrigger.tsx
+++ b/packages/react/src/select/trigger/SelectTrigger.tsx
@@ -101,6 +101,19 @@ export const SelectTrigger = React.forwardRef(function SelectTrigger(
   const timeoutFocus = useTimeout();
   const timeoutMouseDown = useTimeout();
   const selectedDelayTimeout = useTimeout();
+  const openingReleaseListenerRef = React.useRef<{
+    doc: Document;
+    markReleased: () => void;
+  } | null>(null);
+
+  const detachOpeningReleaseListener = React.useCallback(() => {
+    const pending = openingReleaseListenerRef.current;
+    if (pending == null) {
+      return;
+    }
+    pending.doc.removeEventListener('mouseup', pending.markReleased, { capture: true });
+    openingReleaseListenerRef.current = null;
+  }, []);
 
   React.useEffect(() => {
     if (open) {
@@ -125,9 +138,14 @@ export const SelectTrigger = React.forwardRef(function SelectTrigger(
     };
 
     timeoutMouseDown.clear();
+    detachOpeningReleaseListener();
 
     return undefined;
-  }, [open, store, timeoutMouseDown, selectedDelayTimeout]);
+  }, [open, store, timeoutMouseDown, selectedDelayTimeout, detachOpeningReleaseListener]);
+
+  React.useEffect(() => {
+    return detachOpeningReleaseListener;
+  }, [detachOpeningReleaseListener]);
 
   const mergedProps: HTMLProps = mergeProps<'button'>(
     triggerProps,
@@ -201,8 +219,22 @@ export const SelectTrigger = React.forwardRef(function SelectTrigger(
           store.setOpen(false, createChangeEventDetails(REASONS.cancelOpen, mouseEvent));
         }
 
-        // Firefox can fire this upon mousedown
+        // Firefox can fire `mouseup` during `mousedown`. Arm the close listener on the
+        // next task, and skip it when this press was already released.
+        let released = false;
+        function markReleased() {
+          released = true;
+        }
+
+        detachOpeningReleaseListener();
+        doc.addEventListener('mouseup', markReleased, { capture: true });
+        openingReleaseListenerRef.current = { doc, markReleased };
+
         timeoutMouseDown.start(0, () => {
+          detachOpeningReleaseListener();
+          if (released) {
+            return;
+          }
           doc.addEventListener('mouseup', handleMouseUp, { once: true });
         });
       },