巴塞尔（又称为巴泽尔，德：Basel，法：Bâle，意：Basilea）是瑞士的第三大城市（仅次于苏黎世和日内瓦），为巴塞尔城市州（德Basel-Stadt，法Bâle-Ville）的首府，坐落于瑞士西北的三国交角，西北邻法国阿尔萨斯，东北与德国南北走向的黑森林山脉接壤；而莱茵河在此东注北涌穿城而去，将巴塞尔一分为二，版图较大者位于西岸称为大巴塞尔区，小巴塞尔区则位于东岸。

巴塞尔与邻近的自治市里恩（Riehen）和贝廷恩（Bettingen BS）以及与城市附近的古老渔村克莱恩许宁恩（Kleinhüningen）联合形成巴塞尔城市州。

Basel (also Basle /ˈbɑːzəl/; German:Basel [ˈbaːzəl]; French:Bâle [bɑːl]; Italian:Basilea [baziˈlɛːa]) is a city in northwestern Switzerland on the river Rhine. Situated at the Swiss-German-French tripoint, the Basel region culturally extends into German Baden-Württemberg and French Alsace. Basel was the seat of a Prince-Bishopric since the 11th century, and joined the Swiss Confederacy in 1501. Basel had been a commercial hub since the Renaissance, and it emerged as a centre for the chemical and pharmaceutical industry in the 20th century.