旧金山湾区（英语：San Francisco Bay Area）简称湾区（The Bay Area），是美国加利福尼亚州北部的一个大都会区，位于沙加缅度河下游出海口的旧金山湾四周，其中包括多个大小城市，最主要的城市包括旧金山半岛上的旧金山，东部的奥克兰，以及南部的圣荷西等。旧金山湾区为美国西岸仅次于洛杉矶的最大都会区，总人口数在700万以上，该地也是美国人均所得最高的地区之一。

不像其他以单一城市为中心的大都会区，旧金山湾区里有数个独特的城郊中心。虽然圣荷西在1990年人口普查时超越旧金山，成为湾区里人口最多的城市，但旧金山仍旧是湾区的商业与文化中心。

The San Francisco Bay Area (referred to locally as the Bay Area) is a populous region surrounding the San Francisco and San Pablo estuaries in Northern California. The region encompasses the major cities and metropolitan areas of San Jose, San Francisco, and Oakland, along with smaller urban and rural areas. The Bay Area's nine counties are Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, and Sonoma. Home to approximately 7.65 million people, the nine-county Bay Area contains many cities, towns, airports, and associated regional, state, and national parks, connected by a network of roads, highways, railroads, bridges, tunnels and commuter rail. The combined statistical area of the region is the second-largest in California (after the Greater Los Angeles area), the fifth-largest in the United States, and the 43rd-largest urban area in the world.