Because of its high tissue penetrative depth, high remote spatiotemporal selectivity, and noninvasive therapeutic features, sonodynamic therapy (SDT) has received much attention in recent years. In the SDT, a tumor-localizing sonosensitizing agent is activated by ultrasound and produces greatly reactive oxygen species (ROS) to kill tumor cells. Sonosensitizers, including some organic/inorganic compounds and micro/nanoscale sonosensitizers, are an important element in SDT. Herein, we will introduce the organic/inorganic sonosensitizers and advanced micro/nanosized sonosensitizers applied in SDT. At the same time, some perspectives and the future challenges of SDT will be discussed in this review.