In the Book of Mormon, Laman and Lemuel are the two eldest sons of Lehi and the older brothers of Nephi. According to the text, they lived around 600 BC. They were notable for their rebellion against Lehi and Nephi, becoming the primary antagonists of the First and Second Books of Nephi. They and their descendants became known as the Lamanites, while the descendants of Nephi and their other brothers became the Nephites.
Lemuel was Lehi's second-born son. He rejected the teachings of his father (in particular Lehi's prophecy of the forthcoming destruction of Jerusalem in 600 BC.) They persecuted and beat their brothers Sam and Nephi, who supported Lehi. Lemuel seems to have mostly followed Laman's lead in all encounters.