卡迪夫（英语：Cardiff，威尔斯语：Caerdydd），是英联邦威尔斯首府，英国第十六大城市，威尔斯公国最大城市，威尔斯议会所在地。人口约519,700，面积190平方公里。

卡迪夫本是威尔斯南部海岸的一个小镇，19世纪成为重要海港，以运送煤炭到各主要工业重镇为主，1905年被列作城市，1955年成为威尔斯公国首府。

卡迪夫不论人口和人口密度都在威尔斯排名第一，其中白人占91%左右。

卡迪夫是威尔斯重要的旅游中心，千年体育场和Torchwood中心都坐落于此，2010年共有1830万人次到来，也是最热门的旅游目的地。。加迪夫也是电视剧火炬木的舞台。

Cardiff (/ˈkɑːrdɪf/; Welsh:Caerdydd [kairˈdiːð, kaˑɨrˈdɨːð]) is the capital and largest city in Wales and the tenth largest city in the United Kingdom. The city is the country's chief commercial centre, the base for most national cultural and sporting institutions, the Welsh national media, and the seat of the National Assembly for Wales. The unitary authority area's mid-2011 population was estimated to be 346,100, while the population of the Larger Urban Zone was estimated at 861,400 in 2009. The Cardiff metropolitan area makes up over a third of the total population of Wales, with a mid-2011 population estimate of about 1,100,000 people. Cardiff is a significant tourist centre and the most popular visitor destination in Wales with 18.3 million visitors in 2010. In 2011, Cardiff was ranked sixth in the world in National Geographic's alternative tourist destinations.