Trimethylstibine is an organoantimony compound with the formula Sb(CH<sub>3</sub>)<sub>3</sub>. It is a colorless pyrophoric and toxic liquid. It is synthesized by treatment of antimony trichloride and methyl Grignard reagent.
It is produced by anaerobic bacteria in antimony-rich soils. In contrast to trimethylphosphine, trimethylstibine is a weaker Lewis base. It is used in the production of some III-V semiconductors.