Adolescence is a formative stage of life, marked by rapid psychological, emotional, and social development. Mental well-being (MWB) during this period is essential for fostering resilience, academic success, and healthy interpersonal relationships. This study aimed to assess the overall level of MWB among secondary school students and to explore potential differences based on gender across its six dimensions. A sample of 503 students from 21 government schools was selected using random sampling. Data were collected using the 54-item version of Ryff’s Psychological Well-Being Scale, which measures six core dimensions: autonomy, environmental mastery, personal growth, positive relations, purpose in life, and self-acceptance. Descriptive statistics and independent samples t-tests were applied for analysis. The findings indicated moderate to high levels of MWB, with no statistically significant differences between male and female students. Among the six dimensions, students scored highest in purpose in life and lowest in environmental mastery. These results highlight the importance of incorporating well-being promotion into school environments.