The Mongalla free-tailed bat was first described as Nyctinomus demonstrator by the British mammalogistOldfield Thomas in 1903 on the basis of an adult male specimen collected from Mongalla, South Sudan.[4] It was moved to the genus Tadarida in 1914 when Nyctinomus was lumped with the former by Marcus Ward Lyon Jr.[5] In 1983, Patricia Freeman raised Mops from a subgenus within Tadarida to a full genus and included the Mongalla free-tailed bat within it.[6] The species is also called the Mongalla mops bat and Mongallan mops bat.[1] It has no recognized subspecies.[7]
Within its genus, the Mongalla free-tailed bat is placed in the subgenus Mops. Within the genus, it is most closely related to the white-bellied free-tailed bat, which has sometimes been treated as a subspecies of the present species.[7] Its relationship to other species in the genus are unclear, with a 2015 morphological study by Renato Gregorin and Andrea Cirranello finding relationships within Mops to be uncertain.[8]