Kathleen is a popular given name of Irish origin, meaning "pure, bright." It is derived from the Irish name Cáitlín, which itself comes from the Latin name Cathalina, a feminine form of Cathel, meaning "pure" or "chaste." Kathleen was quite common in Ireland during the Middle Ages but gained significant popularity outside of Ireland in the late 19th and early 20th centuries. Today, it is still widely used as a given name for girls around the world. Some notable individuals with this name include American poet Kathleen Norris, British historian Kathleen Thompson, and Irish actress Kathleen Turner.
Kathlen experienced a peak in popularity during the late 1940s to early 1950s with at least five babies named Kathlen born each year from 1946 to 1953, and again in 1956. The name then saw a decline until it resurged slightly in 1965. After that, there was another drop-off with only two occurrences recorded in the late 1990s. Overall, Kathlen has been given to eighty-five newborn girls since 1946.