Ethna is a feminine Irish given name.
Notable people with the name include: Ethna Byrne-Costigan (1904–1991), Irish academic and writer Ethna Carbery (1864–1902), Irish journalist, writer and poet Ethna Gaffney (1920–2011), Irish professor and scientist Ethna MacCarthy (1903–1959), Irish poet and paediatrician Ethna Rouse (born 1937), former New Zealand cricketer Ethna Beulah Winston (1903–1993), American educator