Bang Yai (, ) is one of the six subdistricts (tambon) of Bang Yai District, in Nonthaburi Province, Thailand. The subdistrict is bounded by (clockwise from north) Ban Mai, Bang Mae Nang, Bang Muang, Sala Klang and Sala Ya subdistricts. In 2020, it had a total population of 20,616 people.
The subdistrict is subdivided into 6 administrative villages (muban).
The area of the subdistrict is shared by two local administrative organizations.