Maleinos (Greek: Μαλεΐνος) was the surname of a Byzantine Greek family, first attested in the 9th century, which rose to be amongst the most important and powerful members of the Anatolian aristocracy (the dynatoi) in the 10th century, providing many senior generals to the Byzantine army. After its wealth and power became the target of Byzantine emperor Basil II (r. 976–1025), it declined, although its members are still attested in Anatolia and the Balkans throughout the 11th and 12th centuries.
The family, of Greek origin, first appears in the second half of the 9th century. It has been suggested that the surname derives from the location of Malagina in Bithynia, however its main estates and power-base were in the theme of Charsianon in Cappadocia, which must be considered its proper homeland.
The first known member of the family was the general Nikephoros Maleinos, of whom it is only known that in 866 he suppressed the revolt of Symbatios, a relative of the recently murdered Caesar Bardas. The patrikios and general Eustathios Maleinos, attested later in the century, was probably a brother or son of Nikephoros. Eustathios's son, Eudokimos, married the daughter of a patrikios Adralestos, who was related by marriage to the Emperor Romanos I Lekapenos (r. 920–944).
Eudokimos had seven children, the most prominent among them were Constantine and Michael Maleinos. Constantine was a general and long-time governor (strategos) of the theme of Cappadocia in the middle of the 10th century. From his post, Constantine participated in several campaigns against the Arabs. Michael became a monk at a young age and achieved great fame. He was the mentor of Athanasius the Athonite and was a spiritual advisor to his nephews, the brothers Nikephoros Phokas (the future emperor Nikephoros II, r. 963–969) and Leo Phokas, born to an unnamed sister, the wife of the general Bardas Phokas the Elder. Leo Maleinos, presumably a son of Nikephoros Maleinos, participated in battles against the Arabs in Syria and was killed in 953.