Lady Charlotte Guest (1812–1895) was a nineteenth-century English antiquarian, polymath, and translator. After moving to South Wales with her first husband, she took up the study of Welsh and became the first translator to publish a significant corpus of Middle Welsh prose narratives in modern English. Her translated tales, collectively titled The Mabinogion, were first published between 1838 and 1845. They became instrumental in the popularization and accessibility of medieval Welsh writing in English and other non-Welsh languages.