Castra Galbae was an ancient city and diocese in Africa Proconsulare. It is now a Roman Catholic titular see.
Castra Galbae, apparently named after a member of the Galba family (including an ephemerous general-emperor), was among the towns, important enough in the Roman province of Numidia (in the papal sway) to become a suffragan diocese.
Its only historically documented bishop, Lucius, took part in the Council of Carthage called in 256 by Saint Cyprian, bishop of Carthage), concerning the lapsi, 'fallen' Christians who accepted forced pagan sacrifices to avoid martyrdom.
The bishopric faded, plausibly during the 7th century advent of Islam, but the town persisted in modern Algeria, under the Arabic equivalent of its ancient name: Kasr-Galaba (kasr also meaning fortified place).
The diocese was nominally restored in 1933 as titular bishopric of Castra Galbæ (Latin) / Castra di Galba (Curiate Italian) / Castrensis Galbæ (Latin adjective).
It has had the following incumbents, so far of the fitting Episcopal (lowest) rank, including one of Byzantine Rite: