二氧化锡是一种无机化合物，化学式为SnO₂。

白色、淡灰色或淡黄色六方、斜方或四方晶系粉末，在空气中加热时稳定。在自然界中以锡石存在。结晶成金红石型结构，其中锡六配位，氧为三配位。不溶于水、王水和醇，溶于碱金属氢氧化物溶液中生成锡酸盐，也可溶于酸中，因此为两性氧化物。有导电性能。它一般认为是一种缺氧n型半导体。

二氧化锡可溶于氢卤酸生成六卤锡酸盐，例如它与氢碘酸在回流条件下反应数小时后，可得六碘锡酸。

二氧化锡也可溶于硫酸生成硫酸锡：

Tin (IV) oxide, also known by the systematic name stannic oxide in the older notation, is the inorganic compound with the formula SnO₂. It is not named tin dioxide because Tin is a Type II Metal, and so is named Tin (IV) Oxide by nomenclature. The mineral form of SnO₂ is called cassiterite, and this is the main ore of tin. With many other names (see infobox), this oxide of tin is the most important raw material in tin chemistry. This colourless, diamagnetic solid is amphoteric.