Abstract Nectar composition and concentration were analyzed for 75 samples of 70 species of Acanthaceae representing all major intrafamiliar groups. Analyses of variance were conducted to test for significant differences between pollination syndromes and between taxonomical or phylogenetic groups (∼genera). The available data indicate that the characteristics of nectar in Acanthaceae are predominantly determined by adaptation to needs of the pollinators rather than by phylogenetic constraints.