Background: In pregnant adolescents, it is hypothesized that there is ‘nutrient partitioning’, a competition for nutrients between the still-growing adolescent mother and her rapidly developing fetus Resultsing in a compromised nutrition status of both. This scoping review examined the prevalence of undernutrition, associated factors, and outcomes of adolescent pregnancy. Methods: We used a five stages framework of Arksey and OMalley (2005) to carry out this scoping review. Published articles, reviews, and reports were identified through a complete search. We included articles published in the English language from 2000 to 2020. We summarized the prevalence, associated factors, and health outcomes of pregnancy during adolescence. Results: 25 studies met the inclusion criteria. 32% of the studies are on dietary intake, 20% of them reported nutritional status and associated factors, and 48% of studies discussed the effect of poor nutrition on the outcome of Pregnancy during adolescence. Only 4 of the studies are community-based and 21 are facility based. The magnitude of undernutrition among pregnant adolescent girls ranged from 23.5% to 34%; Social determinants of health such as poor access to antenatal care visits, low educational status of partners, poor dietary intake, early marriage, rural residency, young age and having multiple pregnancies are associated with poor nutritional status. Pregnant adolescents have also more risks of poor pregnancy outcomes compared with pregnant adult women. These include fetal complications like prematurity, low or very low birth weight, and perinatal mortality,  major congenital defects; hypertensive pregnancy disorders, abortion, urinary infections, and premature rupture of the fetal membranes. Conclusions: A higher magnitude of undernutrition, less dietary intake, and more risks of poor pregnancy outcomes were observed from reviewed studies. This review demonstrated the absence of comprehensive literature which might be explored through a population-based prospective study.