The main goal of this study was to develop and test the effectiveness of the PERMA model-based psychological wellness program that was intended for the students Southbay Montessori School and Colleges Inc. A quasi-experimental research design was utilized as the research design and purposive sampling technique for the selection of respondents. The data were gathered from the said institution in Sta. Cruz, Laguna. The respondents of the study were composed of Senior High School and College students in the said school. The researcher utilized an adopted questionnaire as the instrument of the study. As for the statistical treatment, mean formula and paired samples t-test were used.                 As the result revealed, it was found that there was a significant finding on the dimensions of Autonomy, Environmental Mastery, Positive Relations, Purpose in Life, and Self-Acceptance. It revealed that there was a significant difference between the Psychological Well-being of students prior and after the intervention program. As an output, a psychological wellness program was proposed which was intended for the students of Southbay Montessori School and Colleges, Inc. The proposed output program would tackle the different dimensions of the PERMA Model and its effect on the psychological well-being of the students.