正丁醛，简称丁醛，结构式CH₃CH₂CH₂CHO。

无色透明有窒息性刺激气味液体。可燃。微溶于水，与乙醇、乙醚、丙酮、甲苯、乙酸乙酯、油类等多种有机溶剂混溶。对呼吸道粘膜有刺激作用。

Butyraldehyde, also known as butanal, is an organic compound with the formula CH₃(CH₂)₂CHO. This compound is the aldehyde derivative of butane. It is a colourless flammable liquid with an acrid smell. It is miscible with most organic solvents.