Tannahill is a surname. Notable people with the surname include:
Jordan Tannahill (born 1988), Canadian playwright and filmmaker Mary Tannahill (1863–1951), American artist Reay Tannahill (1929–2007), British author and historian Robert Tannahill (1774–1810), Scottish poet
Other The Tannahill Weavers, traditional Scottish musical group active since 1968 Tannehill (disambiguation)