This study evaluated the effectiveness of a depression literacy program on depression literacy, mental health stigma, and help-seeking attitude among adolescents with a monthly household income of RM3900 a month or less (B40) in Malaysia. The program included a lecture, mental awareness activities, and a short video on depression. Residents from a boarding school for lower income families were involved in this study (N = 101); 53 of them underwent the program and another 48 served as the control group. There were significant improvements for all variables in the intervention group (better depression literacy, reduced self-stigma, reduced negative beliefs on mental health, and increased help-seeking) at posttest. However, the results were sustained at 3-month follow-up only for the depression literacy, mental help-seeking attitude, and self-stigma of seeking help variables when compared with the control group. The findings highlight the need to improve the program to enhance the effectiveness and sustainability of the outcomes.