景天科，是虎耳草目的一科，为多年生草本或低矮灌木。原产于世界温暖干燥地区，分布在北半球大部分区域，品种繁多，大约有34属1426种，中国有13属（2特有属，一引进属），约233种（129特有种，1引进种），，另有多种引进作为观赏花卉。

景天科之下共分为六个亚科，分别是：

The Crassulaceae, also known as the stonecrop family or the orpine family, are a family of dicotyledons with succulent leaves. They are generally herbaceous but there are some subshrubs, and relatively few treelike or aquatic plants. They are found worldwide, but mostly occur in the Northern Hemisphere and southern Africa, typically in dry and/or cold areas where water may be scarce. The family includes approximately 1,200-1,500 species and 34 genera.