Yes — for baking performance, not food safety. Baking powder is a chemical leavener (baking soda plus acid salts and usually cornstarch). It does not typically spoil like perishable food, but it gradually loses its ability to release carbon dioxide, so cakes and biscuits can bake flat or dense.
America’s Test Kitchen found that the common hot-water bubble test can still look fine even after a year, while real rise in biscuits started dropping around six months open and was about half as tall by ten months. Their practical advice: mark the open date and replace opened baking powder after about six months if stored cool and dry. Source: America’s Test Kitchen — Baking Powder Shelf Life.