Papaioannou (Greek: Παπαϊωάννου) is a Greek surname. Notable people with the surname include:
Charalampos Papaioannou (born 1972), Greek judoka
Dimitris Papaioannou (born 1964), Greek choreographer, director, dancer and artist
Ezekias Papaioannou (1908–1988), Cypriot politician
Giannis Papaioannou (1913–1972), Greek songwriter
Ioannis Papaioannou (born 1976), Greek chess grandmaster
Makis Papaioannou (born 1977), Cypriot footballer
Mimis Papaioannou (born 1942), Greek footballer
Pavlos Papaioannou (born 1959), Greek footballer
Yiannis Papaioannou (1910–1989), Greek composer