亚硫酸钡是钡的亚硫酸盐，分子式为BaSO₃。作为白色粉状物，可以用于造纸。像其他的钡化合物一样，它是有毒的。

它可以由二氧化硫与氢氧化钡或氧化钡反应制得。

Barium sulfite is the barium salt of sulfurous acid with the chemical formula BaSO₃. It is a white powder which is used in paper manufacturing. Like other barium compounds, it is toxic.

It may be formed by the action of sulfur dioxide on barium oxide or barium hydroxide. It can also be formed by treating barium with sulfurous acid.