Boos is a municipality in the district of Unterallgäu in Bavaria, Germany. It lies in the Swabian region of the state, within the administrative district of Swabia.
The town serves as the seat of a municipal association (Verwaltungsgemeinschaft) that also includes the neighbouring municipalities of Fellheim, Heimertingen, Niederrieden and Pleß. This arrangement makes Boos the administrative centre for the group of communities.