张果（？-？），唐代一位精通服气，修炼内丹的道士，中唐以后，逐渐被神话，后来成为民间神话中的八仙之一，被称为张果老。

张果生卒年月不详；他的故事最早见于《明皇杂录》卷下：“张果者，隐于恒州条山。常往来汾晋间，时人传有长年秘术，……唐太宗、高宗屡征之不起，则天召之出山，佯死于妒女庙前。……后有人于恒州山中复见之。” ；生平又见于《大唐新语》卷10，《新唐书·张果传》乃至于《资治通鉴》卷214开元二十二年载“方士张果自言有神仙术……”，基本均取材于此。

武则天曾谴使欲召见之，即佯死；后人又见到他居于恒州山中，常倒骑白驴，日行数万里，休息时候又将毛驴折叠藏于巾箱；他曾被唐玄宗召见至京师，演出种种法术，授以光禄大夫，赐号通玄先生。

Zhang Guo, better known as Zhang Guolao is a Chinese mythological figure and one of the Eight Immortals in the Taoist pantheon. Among the Eight Immortals, Zhang Guolao, Zhongli Quan and Lü Yan were real historical figures. His existence is said to have begun around the middle or end of the 7th century, and ended approximately in the middle of the 8th. The epithet "Lao" added at the end of his name means "old".