Totsuka-ku (戸塚区) is one of the 18 wards of the city of Yokohama in Kanagawa Prefecture, Japan. As of 2010, the ward had an estimated population of 273,418 and a density of 7,640 persons per km2. The total area was 35.70 km2.

Yokohama is the second-largest city in Japan by population and by area, and the country's most populous municipality. It is the capital and most populous city in Kanagawa Prefecture, with a population of 3.7 million in 2023. It lies on Tokyo Bay, south of Tokyo, in the Kantō region of the main island of Honshu. Yokohama is also the major economic, cultural, and commercial hub of the Greater Tokyo Area along the Keihin Industrial Zone.