International Blue Cross (IBC) has mandated the Swiss company RANAS to evaluate its projects in Chad and Congo as an expert advisor on human behavior change. This external evaluation assessed the life skills and peer education projects in Chad and Congo between 2017 and 2020 and reviewed the projects’ relevance, effectiveness, efficiency, impact and sustainability. By conducting desk review, key informant interviews, focus group discussions and interviews with beneficiaries, evaluators were able to clearly determine that IBC’s work in Chad and Congo has a strong impact on substance abuse and related behaviours (sexual risk behaviours and GBV), the related knowledge and attitudes. The impact of IBC’s local work goes beyond the effect on beneficiaries, influencing communal, structural, and governmental levels by changing people’s perception about substance abuse and even encouraging legal changes.The evaluation underlined that the projects are highly relevant in both countriesand positively impacted the targeted groups. It also recommended that IBC’s work should be extended to more areas worldwide where populations are suffering from substance abuse and related negative behaviours. Furthermore, the implemented projects were deemed sustainable and likely to maintain effects for a reasonable amount of time, as the behaviours are changed, leading to life-long improvements in the lives of beneficiaries, their families and communities. IBC is honored to have a positive impact which actively contributes to the achievement of the United Nation’s Sustainable Development Goals, in addition to contribution to a more peaceful, just, and inclusive societies.