Bang Si Mueang (, ) is one of the ten subdistricts (tambon) of Mueang Nonthaburi District, in Nonthaburi Province, Thailand. Neighbouring subdistricts are (from north clockwise) Sai Ma, Suan Yai (across the Chao Phraya River), Bang Phai, Bang Si Thong and Bang Krang. In 2020, it had a total population of 24,718 people.
The subdistrict is subdivided into 5 villages (muban).
The whole area of the subdistrict is covered by Bang Si Mueang Town Municipality ().