BACKGROUND: This study aimed to investigate the effect of group cognitive behavioral therapy (CBT) on depression, anxiety, stress, and self-esteem in public health students at the University in Southern Thailand. MATERIALS AND METHODS: The study employed a quasi-experimental, one-group, and pre-test -post-test design. Purposive sampling was employed to include 31 students, selected from those with screening indicating mild to moderate depression. While 28 of them (90.3%) were female, three (9.7%) were male. Their age range was 18-21 years, averaging 19.5 years. The instruments were the Thai translation of the Depression, Anxiety, and Stress Scale (DASS-21) and the Thai version of the Rosenberg Self-Esteem Scale (RSES), which were evaluated and produced high validity and reliability results. Data was collected through online questionnaires. A pre-test and a post-test were utilized to measure the participants' depression, anxiety, stress, and self-esteem before and after participating in a group CBT, comprising eight sessions in two months. RESULTS: Revealed significant improvements in depression (P = .001), anxiety (P = .040), and stress (P = .002), while self-esteem (P = .465, >.05) was not significant. CONCLUSION: Group CBT sessions were effective at relieving depression, anxiety, and stress, but not self-esteem. Accordingly, further studies might consider these results and expand on this topic by broadening the population to different majors.