Teagan is of Irish origin, derived from the Gaelic surname Ó Tuathail, which means 'descendant of Tuathal'. This name has a strong historical significance as it is associated with early Irish kings and chieftains. The name gained popularity in English-speaking countries during the late 20th century, often used as a given name for both boys and girls. It has been widely accepted due to its unique sound and attractive spelling.
The name Teagen experienced a notable increase in popularity from the late 1990s to the early 2010s, with the highest number of births occurring in 2011 (57 births). However, since then, its popularity has decreased significantly.