凌志IS（Lexus IS）是丰田汽车公司旗下凌志品牌的入门级豪华轿车／小型行政座驾系列。据凌志官方解释，IS意思是「Intelligent Sport」（智能运动车）的意思。IS被定位于ES系列之下作为入门级豪华汽车，与宝马3系、平治C级和及日产Skyline／InfinitiG35等运动轿车成为竞争对手。在日本，IS系列最初以「丰田Altezza」名义发售，直至在2005年正式引进凌志品牌，推出第二代IS为止。不过「Altezza」的名称仍然用以描述一些装上了类似第一代型号上用上的镀铬尾灯设计的汽车。

The Lexus IS is a series of entry-level luxury cars sold by Lexus since 1998. The IS was introduced as an entry-level sport model slotted below the ES in the Lexus lineup (and outside of North America, the Lexus GS). The IS was originally sold under the Toyota Altezza nameplate in Japan (the word altezza is Italian for "highness") until the introduction of the Lexus brand and the second-generation Lexus IS design in 2006. The Altezza name is still used at times to refer to chromed car taillights like those fitted to the first-generation model, known as 'Altezza lights'