宪法号护卫舰（英语：USS Constitution, IX-21），是一艘现役的美国海军木壳三桅风帆护卫舰，该舰由美国首任总统华盛顿命名，舰名是为纪念于1789年生效的美国宪法。宪法号是美国海军成立初期根据1794年海军法案所授权建造的六艘风帆护卫舰当中的第三艘。目前宪法号是全球舰龄最大的在役海军舰艇，自1797年入役以来，该舰已经在美国海军持续不断地服役超过200年。

尽管宪法号今天仍然服役于美国海军，但不同于其他在役舰艇，宪法号今天已经不再运行军事任务，改而肩负起向公众和游客宣传和推广美国海军历史传统的公关任务。目前宪法号停泊于位处波士顿的查尔斯顿海军基地一号码头，并且拥有一支总人数60人的舰员队伍。和美国海军其他在役舰艇相同，这60名舰员全部隶属在役的水手和军官，他们在海军部的编制内被视为特殊任务人员。。

USS Constitution is a wooden-hulled, three-masted heavy frigate of the United States Navy, named by President George Washington after the Constitution of the United States of America. Launched in 1797, Constitution was one of six original frigates authorized for construction by the Naval Act of 1794 and the third constructed. Joshua Humphreys designed the frigates to be the young Navy's capital ships, and so Constitution and her sisters were larger and more heavily armed and built than standard frigates of the period. Constitution was built in the North End of Boston, Massachusetts, at Edmund Hartt's shipyard. Her first duties with the newly formed U.S. Navy were to provide protection for American merchant shipping during the Quasi-War with France and to defeat the Barbary pirates in the First Barbary War.