Objective: The development of bacterial pathogens that are resistant to many drugs poses a major threat to global health care. Some of the bacteria are Pseudomonas aeruginosa that are considered very difficult opportunist because of their drug-resistance nature and ability to form biofilms. With this situation, the identification of new antimicrobial compounds from natural sources takes an important role. Therefore, in this study, the purpose was to find out the effect of Camellia sinensis extract on Pseudomonas aeruginosa bacteria. Methods of Work: The study used ten isolates obtained from patients with different diseases. These included the tests for antibacterial activity using the agar well diffusion test, MIC test, and MBC test. Various concentrations of green tea extract were used, namely 25, 50, 75, and 100 mg/mL. Ciprofloxacin acted as positive control while distilled water was the negative control. Results: The inhibition zone was between 8 to 17 mm. The highest inhibition zone was recorded for ciprofloxacin (22 mm). MIC ranged from 0.8–2 mg/mL, whereas MBC was within the range of 2–4 mg/mL. Statistical significance through one-way ANOVA analysis indicated extremely significant differences among the treatments (p < 0.001). Antibacterial activity can be explained by the presence of catechins and polyphenols found in green tea. This means that green tea extract could be a promising alternative for fighting bacteria that have developed resistance.