Gibbons, Family Hylobatidae Gray, 1870, are small, arboreal apes of the tropical and semi-deciduous forests of southeast Asia and parts of south and east Asia. Four genera and about 14 species are currently recognized; a number of them threatened with extinction. Two of the reasons for breeding gibbons in captivity are to retain species and subspecies diversity and to create a viable gene pool, with the ultimate goal of releasing animals into protected native habitat. Accurate taxonomic identification may be complicated for some gibbon species due to (1) variation in coat color, (2) sexual dichromatism, and (3) the occurrence of coat color changes from infancy through sexual maturity, and for all species because of (4) the impacts of such as malnutrition and housing on coloration (for example, their maintenance indoors only or in full sunlight), (5) the ease with which the vocalizations of the different species can be confused, (6) the difficulties in distinguishing some gibbon subspecies from each other, and (7) errors in, or the lack of, information concerning the origin of confiscated gibbons. Given these problems, it is not surprising that rescue and breeding centers encounter difficulties in identifying the gibbons they receive. I review the characteristics and identifying features of the species and subspecies of gibbons, including information from museum specimens, live gibbons housed at the Gibbon Conservation Center, Santa Clarita, California, and a number of zoos worldwide.