Butyl methacrylate is the organic compound with the formula C<sub>4</sub>H<sub>9</sub>O<sub>2</sub>CC(CH<sub>3</sub>)=CH<sub>2</sub>. A colorless liquid, it is a common monomer for the preparation of methacrylate polymers. It is typically polymerized under free-radical conditions.
In terms of the acute toxicity of butyl methacrylate, the is 20 g/kg (oral, rat). It is an irritant to the eyes and can cause blindness.