Benzothiazole and its derivatives (collectively referred to BTHs) are used widely in many consumer (e.g., textiles) and industrial (e.g., rubber) products. Very little is known about the occurrence of BTHs in indoor air and the inhalation exposure of humans to these substances. In this study, 81 indoor air samples collected from various locations in Albany, New York, USA, in 2014 were analyzed for BTHs by high-performance liquid chromatography-tandem mass spectrometry (HPLC–MS/MS). BTHs were found in all indoor air samples, and the overall concentrations in bulk air (vapor plus particulate phases) were in the range of 4.36–2229 ng/m3 (geometric mean: 32.7 ng/m3). The highest concentrations (geometric mean: 148 ng/m3) were found in automobiles, followed by homes (49.5) > automobile garages (46.0) > public places, e.g., shopping malls (24.2) > barbershops (18.9) > offices (18.8) > laboratories (15.1). The estimated geometric mean daily intake (EDI) of BTHs for infants, toddlers, children, teenagers, and adults through indoor air inhalation from homes was 27.7, 26.3, 17.9, 10.5, and 7.77 ng/kg-bw/day, respectively. The estimated contribution of indoor air to total BTHs intake was approximately 10%. This is the first study on the occurrence of BTHs in indoor air.