Adolescents from indigenous populations in Ratanak Kiri Province in Cambodia experience worse sexual and reproductive health (SRH) outcomes when compared to their urban counterparts. However, few qualitative studies have been conducted to identify factors that may explain the poor SRH outcomes experienced by this population group. The socioecological model was used as the analytical lens to explore the SRH knowledge and sources of SRH information of adolescent mothers (aged 15-19 years) from indigenous populations in north-eastern Cambodia. Adolescent mothers from the Tompoun and Jarai indigenous population groups (n=22) were purposively recruited from seven villages in two districts of Ratanak Kiri Province. All adolescent mothers engaged in a combined body mapping exercise and semi-structured interview; this approach was considered the most appropriate qualitative data collection method to use in this context as it reduced language, cultural and social barriers that have previously restricted qualitative exploration of sensitive issues among this population group. The body maps and semi-structured interview transcripts were analysed using thematic analysis. Adolescent mothers demonstrated limited SRH knowledge including that pertaining to the anatomy of the female reproductive body, the physiology of human reproduction, fertility and pregnancy. Adolescents' primary source of SRH information was interaction with female family members and friends within their community. Adolescents' limited SRH knowledge was influenced by factors on individual (eg educational attainment, child marriage), relationship (eg social interaction with female family members and friends), community (eg access to educational and healthcare services) and societal (eg barriers to accessing national SRH programs and initiatives) levels. The%u202Ffindings support the need for SRH education in the primary and secondary school curriculum. In 2018 the Cambodia Ministry of Education, Youth and Sports introduced a Comprehensive Sexuality Education (CSE) program into the government primary and secondary school curriculum. The CSE, which is delivered in the Khmer language, provides Cambodian youth with an avenue to access accurate SRH information that will aid their SRH decision-making. However, indigenous girls face numerous social, cultural, economic and language barriers that restrict or prevent their access to formal education. Therefore, additional SRH materials and resources that are culturally and linguistically appropriate need to be developed for indigenous students attending primary and secondary schools in Ratanak Kiri Province and for young people who have ceased formal education. Educating village chiefs to deliver non-formal, community-based education programs is proposed as a means of increasing SRH knowledge and reducing health inequalities faced by this population group while ensuring that accurate information is delivered in a culturally appropriate manner.