Xenon tetroxide is a chemical compound of xenon and oxygen with molecular formula XeO4, remarkable for being a relatively stable compound of a noble gas.

It is a yellow crystalline solid that is stable below −35.9 °C; above that temperature it is very prone to exploding and decomposing into elemental xenon and oxygen (O2).

Oxygen is the only element that can bring xenon up to its highest oxidation state; even fluorine can only give XeF6 (+6).

The perxenates are also compounds where xenon has the +8 oxidation state.

One is the disproportionation of xenates to perxenates and xenon: The other is oxidation of the xenates with ozone in basic solution: Barium perxenate is reacted with sulfuric acid and the unstable perxenic acid is dehydrated to give xenon tetroxide:[6] Any excess perxenic acid slowly undergoes a decomposition reaction to xenic acid and oxygen: