吉利服（Ghillie suit），是一种伪装服，外表跟灌木丛相似。最典型的吉利服是用网或布制作的，表面缀满叶子和其他小树枝，可用于迷惑对手。狙击手和猎人会穿上吉利服来配合野外地区伪装自己而不被发现。

吉利服由一名苏格兰的猎场看守人发明的，他用其伪装自己，以便于打中猎物。所以，就以他的名字吉利Ghillie来命名。「吉利」一词的准确读音为“gah-hee-lee”，在苏格兰盖尔语当中的意思是「男孩」；在英格兰用语里，则特别说明是专门用来辅助主人打猎或钓鱼的「佣人」。Ghillie dhu是苏格兰的神话中住在森林或山里, 以树叶, 青苔和树枝为衣服的精灵或守护者。

A ghillie suit (called a yowie suit by the Australian Army) is a type of camouflage clothing designed to resemble the background environment such as foliage, snow, sand, etc. Typically, it is a net or cloth garment covered in loose strips of burlap, cloth or twine, sometimes made to look like leaves and twigs, and optionally augmented with scraps of foliage from the area.