氧化铷（Rb₂O），是铷的氧化物之一，呈黄色，有很强的潮解性。

铷在空气中燃烧时，主要生成的是过氧化铷，只有少量的氧化铷和超氧化铷生成。当金属铷被露置于空气中时，它会很快氧化，失去金属光泽，并产生一系列有颜色的氧化产物。其中生成了铷的低氧化物，例如青铜色的Rb₆O和红棕色的Rb₉O₂。铷最终的氧化产物主要是过氧化铷。

氧化铷主要由用铷还原无水硝酸铷、氢氧化铷或超氧化铷产生：

Rubidium oxide is the chemical compound with the formula Rb₂O. Rubidium oxide is highly reactive towards water, and therefore it would not be expected to occur naturally. The rubidium content in minerals is often calculated and quoted in terms of Rb₂O. In reality, the rubidium is typically present as a component of (actually, an impurity in) silicate or aluminosilicate. A major source of rubidium is lepidolite, KLi₂Al(Al,Si)₃O₁₀(F,OH)₂, wherein Rb sometimes replaces K.