Undernutrition is a major global health issue, especially among children under 5 years old, with millions affected worldwide, particularly in low-income countries like Rwanda. A study aimed to identify factors contributing to this ongoing problem in Rwanda that are not sufficiently addressed by current community interventions. Using a participatory research design, eight open-space meetings were held in two districts in the Northern Province, involving 194 participants, including community health workers and caregivers. The study found several key factors leading to persistent undernutrition, such as parent conflicts, lack of male involvement in childcare, children’s mental health issues, inexperienced caregivers, and insufficient family planning. Despite efforts from governmental and non-governmental organizations, undernutrition remains a critical concern. The research suggests that specific household-related factors need more attention and proposes strategies to effectively tackle them, aiming to reduce undernutrition among young children in Rwanda.