The Best Interest of the Child − Self-report questionnaire (BIC-S) is designed as a tool to ensure young people in secure residential care have a voice about their living environment. The primary aim of this study was to determine the psychometric properties of the BIC-S. Second, we wanted to map the experiences of young people with their current residential living environment. Therefore, both quantitative and qualitative methods were used to assess the experiences of young people with the BIC-S instrument in this cross-sectional study. Based on a sample of 74 young people staying in secure residential care in the Netherlands (2015), we explored the construct validity and reliability of the BIC-S through a Mokken Scale Analysis. The sample consisted of 38 boys and 36 girls (mean age 15.5). After evaluating the psychometric properties of the instrument, we focused on the experiences of young people with their current residential living environment. The results show that eleven out of the fourteen BIC-S conditions form a moderate scale to measure how young people perceive the quality of their living environment (H = .40; Rho = .86). With regard to the residential environment, the participants often raise issues which relate to personal safety, to activities within the institute, or to the relationship they have with care professionals. The results indicate that the BIC-S has the potential to serve as an instrument for young people to voice opinions on their living environment while in residential care.Keywords Construct validity . Self-report questionnaire . Best interest of the child . Secure residential youth care . Mokken scale analysis Child Ind Res