Key Message
This study compared causal models of mental health literacy (MHL) and helping behavior toward people at risk of depression between Thai and Vietnamese health science students. Findings indicated that MHL significantly impacted helping behavior (effect size [ES], 0.91), mediated indirectly by self-efficacy (ES, 0.18), positive attitudes (ES, 0.29), and social support (ES, 0.77), with no significant differences in the overall causal models between groups. However, variations in effects were noted, such as social support having a more pronounced effect on MHL among Vietnamese students than their Thai counterparts (ES, 0.46 vs. 0.27), while positive attitudes had a stronger influence among Thai students (ES, 0.17) than Vietnamese (ES, 0.01).