Poor overall neonatal outcomes, small neonatal head circumference, neonatal hypoglycemia, need for Neonatal Intensive Care Unit and late-onset neonatal sepsis are more common in adolescents. The aim of this study is to draw attention to the outcomes of adolescent pregnancies. This retrospective study was conducted in adolescent singleton pregnancies with maternal age < 15 years (n = 20, group 1), 16-19 years (n = 1929, group 2), and 20 years (n = 866, group 3). Age, gravidity, parity, and body mass index (BMI) measurements of mothers; mode of delivery, maternal and neonatal outcomes were evaluated and compared. The rate of preterm birth, postpartum hemorrhage, asymmetrical intra-uterine growth restriction (IUGR, as 3% percentile), macrosomia, and height of newborn of Group 3 was significantly higher. The rate of asymmetrical IUGR (as 10% percentile) was significantly lower in Group 3. The rate of severe preeclampsia and cesarean section was significantly higher in Group 3. The rate of Small for Gestational Age newborn, neonatal hypoglycemia, and late-onset neonatal sepsis was significantly higher in Group 1. Neonatal problems with poor obstetric outcomes are common in adolescent pregnant women, so that a family planning and baby care social trainings are important in achieving good long-term maternal and neonatal outcomes.