BackgroundEarly marriage and pregnancy is a risk factor for poor maternal and child health and socio-economic outcomes. Bokeo and Luang Namtha provinces in northern Lao People’s Democratic Republic (PDR) has high rates of teenage pregnancy. The purpose of this research was firstly to explore factors contributing to teenage pregnancy in rural Lao. Secondly, to understand the specific challenges adolescent mothers face in accessing maternal health services.MethodsQualitative interviews were undertaken with adolescent mothers and unmarried adolescents aged 12 to 19 years, living in rural areas, and from different ethnic groups. In total, we undertook six focus group discussions with adolescents aged 13–19 years, twenty in-depth interviews with unmarried/married adolescents aged 12–19 years. In addition, we interviewed husbands of the adolescent mothers (N = 8) and mothers-in-law of both male and female adolescents (N = 9), community leaders and healthcare providers (health providers N = 17 and community leaders N = 12). Thematic analysis was used to analyze the data, based on a conceptual framework identified at the outset of the study.ResultsThe findings suggest that pre-marital sex, early marriage and pregnancy are the norm in these settings. Determinants of teenage pregnancy included liberal attitudes to teen pre-marital sexual intercourse, early marriage and pregnancy, incomplete knowledge of sexual and reproductive health and limited access to appropriate services.ConclusionThe determinants of teenage pregnancy in this setting are multi-dimensional, and require a range of responses. As some of the determinants are deeply embedded in the system of local values, beliefs and practices, and form part of the logic of what it is to become a healthy woman, these practices are deeply entrenched and may be resistant to new knowledge. The challenge therefore is to find culturally responsive strategies that enable individual and collectively agency.