Objectives: Barleria, a large genus of the Acanthaceae family, comprises more than 300 species with diverse taxonomy, cytogenetics, phytochemistry and pharmacological potential. Therefore, the aim of this review is to critically assess the research on Barleria and provide guidance for future investigations. Methods: The data were obtained from different sources, such as books, theses, journals and some of the websites and internet-based searches, published from 1901 to 2020. Data obtained from PubMed, Google Scholar, ScienceDirect, online electronic journals, SpringerLink, Wiley, etc. have also been used. Key findings: The species of this genus exhibit considerable medicinal properties. Cytogenetical data are scantily available with chromosome counts available for only 24 species. The most common chromosome number is 2n = 2x = 40. So far, 187 compounds are reported from Barleria species. The active principles, their uses, toxicity and pharmacological effects are discussed. Essential oils, flavones, flavonoids, glycosides, terpenes and terpenoids form the major compounds. Summary: It is highly recommended that the pharmacological and economic potential of Barleria species should be exploited and more detailed studies and attention be geared towards its utilization and conservation. In addition, to ensure maximum pharmacological benefits and sustainable use, it is necessary to have empirical information explaining its ethnobotanical values as well as commercial potential.