Introduction: Aiming at generating evidence for cost-effective public health (PH) interventions for suicidal behaviour (SB) prevention in South Eastern Europe, the objective was to identify adverse childhood experiences (ACEs) most strongly predicting SB in emerging adults. Methods: Survey data of 3283 students aged 18-29 from Montenegro and Romania were analysed by logistic regression. Based on estimation of risk-for-SB, the profiles with the highest values were identified. Results: The SB odds were the highest in respondents, experienced a suicide attempt in the household (OR: 13.81; p<0.001), and whose primary family was not complete, in particular in those with the foster family background (OR: 18.30; p=0.001). Conclusions: Magnitude of impact on emerging adults’ mental health vulnerability tends to vary considerably with individual ACEs. This should be considered carefully when developing cost-effective response to SB burden through PH interventions in particular at the times of financial crises and in scarce resources settings.