While increased attention has been given to girls’ menstrual hygiene management (MHM) experiences in schools as they relate to managerial challenges, research exploring girls’ psychosocial experiences during menstruation and their needs in non-school environments remains limited. This study investigates the knowledge, attitudes, and practices regarding menstruation and MHM (M&MHM) among rural Cambodian girls (at least 14 years old, post-menarche; n = 130), mothers (n = 93), fathers (n = 15), teachers (n = 37; 54.1% female), and boys (at least 14 years old; n = 59) in both the home and school environments. Qualitative and quantitative data were collected through structured interviews, focus groups, and latrine surveys in eight secondary schools and villages from two rural provinces, Banteay Meanchey and Kratie. Findings indicated that although 95% of girls felt capable of managing their menses each month, many girls experienced fear, shyness, and discomfort (FSD) during menstruation. Identified M&MHM challenges and FSD in both the home and school environments influenced all participant groups’ decision-making, social interactions, and varied based on their knowledge of M&MHM and emphasized the need for comprehensive interventions that reduce the impact of MHM challenges on psychosocial experiences and FSD to promote girls’ well-being during menstruation, particularly in income limited settings.