山茶科（Theaceae）大部分属原产于亚洲东部，多分布热带及亚热带地区，南至马来西亚，北至日本，也有几个属是生长在美洲的。

绝大部分山茶科植物是常绿的灌木或乔木，但紫茎属和北美大头茶属是落叶植物。山茶科植物叶为单叶，互生，一般为革质，没有托叶，花常两性，辐射对称，单生，有时簇生，萼片和花瓣常各5枚，雄蕊常甚多，分离或基部结合，或集成5束，子房上位，大多数3-5室，每室有二至数胚珠；果实为裂开的蒴果，近木质，有时肉质不裂。

Theaceae /θiːˈeɪsiː/ is a family of flowering plants, composed of shrubs and trees, including the camellias. It can be described as having from seven to 40 genera, depending on the source and the method of circumscription used. The family Ternstroemiaceae has been included within Theaceae; however, the APG III system of 2009 places it instead in Pentaphylacaceae.