The challenge of finding organic sources of antibacterial activity that are widely available, environment-friendly, and cost-effective with significant antibacterial efficacy, remains persistent especially in developing countries such as the Philippines. In this study, the antibacterial activity of Santan (Ixora coccinea) leaf, Cacao (Theobroma cacao) pod husk, and Betel Palm (Areca catechu) seed extracts against Staphylococcus aureus was assessed. Plant extract concentrations of 25%, 50%, 75%, and 100% were prepared and their antibacterial activity on S. aureus was assessed using the Kirby-Bauer disk diffusion susceptibility test. Antibacterial activities were determined using the zone of inhibition diameter. Distilled water and Penicillin were used as negative and positive controls, respectively. Results showed that Santan (I. coccinea) leaf extract with 75% concentration exhibited the highest antibacterial activity on S. aureus among all plant extracts used. However, its antibacterial activity was comparatively lesser than that of Penicillin. No antibacterial activity of Cacao (T. cacao) pod husk and Betel Palm (A. catechu) seeds extracts on S. aureus was observed. The differences in the zone of inhibition diameter in all extracts on S. aureus were significant (p<0.01).