Introduction: Hibiscus sabdariffa plant has been used in many ways both for industrial purposes and medicinal uses. It has been discovered to have antimicrobial properties. Aim and objective: The present study was aimed to investigate the phytochemical and antimicrobial activities of methanolic and aqueous extracts of H. sabdariffa calyces on Staphylococcus aureus and Escherichia coli. Materials and methods: The phytochemical analysis was carried out using standard methods. The antibacterial activity of the plant extracts was determined using the agar well diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the plant extracts on the test isolates were determined using the micro broth dilution method. Results: The phytochemical analysis showed that terpenoids, phenols, flavonoids, glycosides, tannin, saponin, alkaloids, and anthraquinolones were present in varying concentrations of the different extracts. The methanol extract of H. Sabdariffa calyces possesses more antimicrobial activity (13–24 mm) in a concentration-dependent manner than the aqueous extract (7–20 mm). The MIC of different extracts of S. aureus was between 25 mg/mL and 50 mg/mL while that of E. coli was also between 12.5 mg/mL and 25 mg/mL. The MBC of different extracts of S. aureus was between 25 and 50 mg/mL while that of E. coli was between 6.25 and 50 mg/mL. Conclusion: It can be concluded that some secondary metabolites present in H. sabdariffa calyces was responsible for the observed inhibition of the bacteria seen in this study. The methanol extract of H. sabdariffa calyces possesses more antimicrobial activity in a concentration-dependent manner than the aqueous extract. Therefore, the test plant could be used to manufacture drugs that could be used to treat infections caused by the test organisms.