Pollen morphology of 15 species ofSiphonoglossaand of two closely related groups was investigated. Two tribal‐specific pollen types are found withinSiphonoglossasensu lato suggesting that the genus is artificial, composed of taxa belonging in several genera among two tribes (subtribes sensu Bremekamp) of Acanthaceae. Five taxa currently included in an informal subgeneric category ofSiphonoglossahave tricolporate, prolate pollen (termed Type I) that is characteristic of Odontonemeae (= Odontoneminae, Justicieae). Pollen of the remaining taxa, belonging in two formal sections of the genus, are mostly 2‐porate, bilateral (Type II) with a sexine sculpturing characteristic of Justicieae (= Justiciinae). Pollen of sectionSiphonoglossais rather uniform, 2‐porate, bilateral with lolongate pores, and seem to delimit a natural group. Taxa of sectionPentalobahave a more heterogeneous pollen morphology, mostly 2‐porate, bilateral with lalongate pores. Controversial aspects of the interpretation of pollen morphology in Justiciinae are presented and their relevance to this study are examined. Hypothetical trends in the evolution of pollen of Justiciinae are discussed and the application of pollen morphology to taxonomy of the genus is presented, including a recommendation for narrowing the generic concept ofSiphonoglossato the taxa of the type section.