Robert Lang Campbell (1825-1872) was a convert to the Mormon Church from Scotland, missionary, and a clerk to early Church leaders.

Robert Lang Campbell was born in 1825 to Alexander and Agnes Campbell in Kilbarchan, Renfrewshire, Scotland. Robert was baptized a member of the Church of Jesus Christ of Latter-day Saints in 1842 at the age of seventeen. He served a mission to nearby Dalry, receiving the Aaronic Priesthood in November 1843. He emigrated to Nauvoo in March 1845 and became a member of the Quorum of Seventies, and worked as a clerk for John Smith, William Smith, and Willard Richards.

Robert married Joan Scobe, his sweetheart from Scotland, in November 1845, with the sealing performed one year later. Due to an illness, Robert and Joan had to delay their exit from Nauvoo and were witness to the Battle of Nauvoo in September 1846. Robert and Joan left Nauvoo with other Saints in September 1846, traveling to Winter Quarters in October; where, sadly, Joan delivered a stillborn baby boy, then died herself. Robert continued his clerking and transcribing work until his mission to the British Isles in 1850. While there, he married Mary Stewart. They returned to Salt Lake in 1854, where Robert continued to serve the Church as the Historian's clerk, copying portions of Joseph Smith's History. Plural marriage being in practice, Robert was asked to take additional wives, and married Jeanie Brown.

During his life, Robert also served as secretary of Deseret Agricultural and Manufacturing Society (an elected position), was appointed as a regent of Deseret University, a member of the Legislative Assembly, and elected Superintendent of Schools for Salt Lake County. Robert also acted as Chief Clerk of the House of Representatives of Utah Territorial Legislature, where he worked until his early death April 11, 1872, at the age of 47.