口诀（구결，Gugyeol），又称입겿，是用于表示加注于汉文的朝鲜语助词的朝鲜语文本。口诀用于记录注于汉文中各短语间的朝鲜语助词，以便于文章的阅读与解释。与乡札互相影响，一同发展起来。

吏读也是用汉字表示朝鲜语的表记法，与口诀的不同在于吏读是以朝鲜语自身的语序表记朝鲜语，而口诀夹写于汉文中间，仅是以朝鲜语的方式阅读汉文的辅助手段。借助口诀阅读汉文的方法类似于日本的汉文训读。口诀可以是汉字或汉字的一部分，类似于日本的片假名。由于存在与片假名同音同型的字，两者的关系吸引了研究者的注意。

Gugyeol is a system for rendering texts written in Classical Chinese into understandable Korean. It was chiefly used during the Joseon Dynasty, when readings of the Chinese classics were of paramount social importance. Thus, in gugyeol, the original text in classical Chinese was not modified, and the additional markers were simply inserted between phrases. The Korean reader would then read the parts of the Chinese sentence out of sequence to approximate Korean (SOV) rather than Chinese (SVO) word order. A similar system for reading classical Chinese is used to this day in Japan and is known as Kanbun.