 Tiantai is the name of a mountain and surrounding geographical location in China, literally meaning “platform of the sky”, but the term is traditionally used to denote a particular school of Mahāyāna Buddhism with historical connections to that locale. In this article, the term “Tiantai” will be used to refer to the philosophical ideas developed from the sixth to eleventh centuries by this school, as expounded in the writings of its three most representative figures: Tiantai Zhiyi (538–597), Jingxi Zhanran (711–782) and Siming Zhili (960–1028).