Beta-lactamase production is the main resistance mechanism to beta-lactam antibiotics by Enterobacteriaceae including Escherichia coli. In this study, we selected Terminalia superba, Annona senegalensis, Ipomoea batatas and Psidium guajava, which antibacterial properties have been proved with the aim to evaluate their beta-lactamase inhibitory activity. Production of β-lactamase was determined by modified tube acidimetric method using benzyl penicillin as substrate and phenol red in liquid medium. The tests were carried out on the ability of ethanolic plants extracts to reduce the hydrolysis of benzyl penicillin. Three plant extracts showed beta-lactamase inhibitory activity, with the highest enzyme inhibition rate found with Terminalia superba. Plant extracts with beta-lactamase inhibiting potential can be associated with beta-lactam antibiotics which are no longer effective to overcome the growing resistance to these widely prescribed antibiotics. The finding of this study showed the potential of antibacterial plants in the search for new beta-lactamase inhibitors.