Robert Ballagh (born 22 September 1943) is an Irish artist. He was born in Dublin and is both a painter and designer. His painting style was strongly influenced by pop art and his paintings are often playful and didactic. In 1991, he co-ordinated the 75th anniversary commemoration of the 1916 Easter Rising. Interviewed for a special feature that was published in the Irish Times on the 90th anniversary, he related that this had caused him to be harrassed by the Special Branch of the Garda Siochána.
Ballagh represented Ireland at the 1969 Paris Biennale. Among the theatre sets he has designed are sets for Riverdance, Samuel Beckett's Endgame (1991) and Oscar Wilde's Salomé (1998). He has also designed over 70 Irish postage stamps and the last series of Irish banknotes, "Series C", before the introduction of the euro. He is a member of Aosdána.