We report results of field collections, laboratory rearing, and behavioral observations of tephritids belonging to the tribes Acanthonevrini and Gastrozonini in Malaysia and Thailand. The focus of the study was on general biology, seasonal history, mating, oviposition, larval biology, larval habits, and microhabitats. Host association with bamboo was unequivocally established for 31 species. Adult flies fed on liquids oozing from plants or other sources. Most species developed in the rainy season, when bamboo shoots were available. In Thailand, adult flies gathered along streams in the dry season. Observed sexual behavior patterns appeared to be simple in Gastrozonini, whereas in some Acanthonevrini, the males produced a foamy “nuptial gift,” which was offered to females during courtship. Eggs were laid under sheaths or in injuries to the bamboo surface. The main obstacle to oviposition and penetration of shoots appeared to be the hard culm sheaths.Thelarvae entered feeding substrates via injuries, holes created by other insects, or by squeezing in between culm sheaths and bamboo walls. Larvae of Gastrozonini and Rioxoptilona (Acanthonevrini) fed on living or dead bamboo shoots. Larvae of other Acanthonevrini developed in water-filled internode cavities, scraping particles from walls or collecting them from the water surface. Bamboo growth stages and degree of protection by culm sheaths were used to classify microhabitats. These determined to a large extent which guilds of flies could be found. While larvae of some bamboo tephritids destroyed thin bamboo shoots or branches, most acted as secondary pests and did not cause substantial economic losses.