Miniopterus aelleni is a bat in the genus Miniopterus that occurs on Anjouan in the Comoros and in northern and western Madagascar. It is a small brown bat; its forearm length is 35 to 41 mm (1.4 to 1.6 in). The long tragus (a projection in the outer ear) has a broad base and a blunt or rounded tip. The uropatagium (tail membrane) is sparsely haired. The palate is flat, and there are distinct diastemata (gaps) between the upper canines and premolars.