Sumatra is one of the largest islands. Its location on the equator between two major continents, namely, Asia and Australia, has an effect on its climate, which a type B 60 climate is with high rainfall of up to 130 mm/day. Kweni mango (Mangifera odorata Griff.), which is produced along the West Coast of Sumatra, has superior characteristics, including high productivity and the capability to produce fruits during the off-season. Kweni is distinguished from other commercial mangoes (Mangifera indica L.) by its unique aroma, sweet flavor, and soft fibers. This study aimed to determine the genetic diversity and classification of kweni fruit from Sumatra on the basis of morphological and molecular variations. Fruit samples were collected from the centers of diversity of kweni, including the Aceh, West Sumatra, Riau, and Bengkulu Provinces, in Indonesia. The data on 52 kweni accessions were recorded and analyzed by using 43 morphological characters, and 10 intersimple sequence repeat (ISSR) primers with 94 bands. The morphological characters that divided the kweni accessions into three major groups was the sweetness level of the pulp (°Brix). Group I had the sweetest flavor (16.7-21.0 °Brix), group II had a moderately sweet flavor (12.4-16.66 °Brix), and group III had a sour flavor (8-12.3 °Brix). The ISSR markers separated the kweni accessions into four main groups based on accession origin. Results further revealed that the kweni accessions were morphologically similar but genetically varied. The genetic resources of the kweni fruit used in this study and their classification could be used for the further improvement of mango in Sumatra through future breeding programs. [ABSTRACT FROM AUTHOR]