While studies have shown the importance of pictorial health warnings (PHW) as a tobacco control strategy, empirical evidence on the efficacy of PHW in prompting smoking behavior remains inconclusive. The study aimed to examine the association between PHW and cognitive reactions, emotional/affective reactions, and smoking behavior. We conducted a mixed-methods study, which included a cross-sectional face-to-face survey of 401 smokers in four cities (Jakarta, Bandung, Semarang, and Yogyakarta) and three focus group discussions among 24 participants in Jakarta. We applied multiple logit regression in STATA for quantitative data analysis and explanatory sequential design for qualitative data analysis. Quantitatively, we found high (63-84% of respondents) understanding about PHW objectives (cognitive reactions), including to remind health risks and encourage smoking cessation. With only 40% PHW, we found relatively low (32%-39%) negative emotional reactions, including feeling scared, annoyed and disgusted and relatively low proportions (33-40%) of respondents that reported quit attempt. Consistent with the quantitative findings, qualitative data provided contexts, including in explaining that the professional worker group was the least affected by PHW, while the student and non-professional groups were the most vulnerable. All this is supportive of governments in Indonesia and other countries to increase the PHW size.