过氧化钡（化学式：BaO₂）是钡的过氧化物，是最常见的无机过氧化物之一。室温下为灰白色固体，可用作氧化剂、漂白剂。加入至焰火中时既可作氧化剂，也会产生钡特定的亮绿色光。

过氧化钡中含有过氧根离子O₂，固态时与碳化钙（CaC₂）有相同结构。

氧化钡吸收O₂会生成过氧化钡，该反应可逆，高于700°C过氧化钡分解：

可用该反应来从大气中提取氧气，反应物也可选用氧化钠，机理类似。

过氧化钡与稀硫酸低温反应，过滤，可用于制取双氧水：

Barium peroxide is the inorganic compound with the formula BaO₂. This white solid (gray when impure) is one of the most common inorganic peroxides, and it was the first peroxide compound discovered. Being an oxidizer and giving a vivid green colour upon ignition (as do all barium compounds), it finds some use in fireworks; historically, it was also used as a precursor for hydrogen peroxide.