While the drivers of adolescent pregnancy are widely studied, few studies have examined the social exclusions associated with early and unintended pregnancy. Drawing data from a larger mixed methods study on the lived experiences of pregnant and parenting adolescents and guided by Amatya Sen’s social exclusion framework, this qualitative explanatory study examines how poverty and the contestation around girls’ access to comprehensive sexuality education hinder them from preventing unintended pregnancy. It also examines why adolescent pregnancy further results in girls’ social exclusion with implications for their health and socioeconomic (dis)empowerment. We drew on data from in-depth interviews with purposively selected pregnant and parenting adolescents aged 15 to 19 (n = 22) and parents (n = 10), and key informant interviews with teachers (n = 4), policymakers (n = 3), community leaders (n = 6) non-governmental organization representatives (n = 2), and health workers (n = 4). Through inductive and deductive thematic analysis, we found that poverty and lack of access to contraceptive information and services contributed to girls’ vulnerability to early unintended pregnancies. Becoming pregnant exacerbated girls’ social exclusion, which is characterized by self-isolation, being disowned by their families, or forced to drop out of school. Shame, stigma, and discrimination of girls made girls seek antenatal care late. They also failed to complete the recommended number of antenatal care visits. Marginalization of pregnant and parenting girls results in them being out of school, vocational training, and employment, as well as experiencing mental distress. The analysis shows the social exclusion of girls is cyclical, beginning before their pregnancy and continuing into pregnancy and post-pregnancy. Their social exclusion has negative implications for their health and socio-economic empowerment. Interventions to address adolescent childbearing should holistically address the social exclusion that predisposes girls to unintended pregnancy and that follows during and post-pregnancy, as tackling this exclusion is key to improving their health and socioeconomic well-being.