Adolescents differ from adults not only in biological factors related to age but also in social and psychological characteristics, which may heighten their risk of adverse obstetrical outcomes. This study explores the relationship between maternal age and adverse obstetrical outcomes by comparing adolescent and adult mothers in North Wollo Zone public hospitals, by adjusting for potential confounders such as sociodemographic factors, healthcare access, antenatal care utilization, and pregnancy-related variables. A comparative cross-sectional study was conducted from November 20, 2022, to February 20, 2023, involving 488 mothers to assess adverse obstetrical outcomes among adolescent and adult mothers who gave birth at 28 or more weeks of gestation in North Wollo Zone Public Hospitals, Northern Ethiopia. Data were collected through interviews and clinical chart reviews, then entered into EPI DATA version 4.6.6.0 and analyzed using SPSS version 26. Descriptive statistics summarized the data, and logistic regression identified significant variables (p < 0.05). Adolescent mothers exhibited significantly higher rates of adverse obstetrical outcomes compared to adult mothers, including preterm labor (7.0% vs. 2.0%, p = 0.04), antepartum hemorrhage (11.9% vs. 4.9%, p = 0.014), anemia (19.3% vs. 10.2%, p = 0.006), pregnancy-induced hypertension (11.9% vs. 7.0%, p = 0.047), malpresentation (9.0% vs. 2.5%, p = 0.008), cephalopelvic disproportion (6.1% vs. 1.2%, p = 0.046), major perineal tears (8.6% vs. 3.3%, p = 0.016), and cesarean delivery (16.0% vs. 9.8%, p = 0.04). Adolescent pregnancy is strongly linked to a range of adverse obstetrical outcomes, including preterm labor, antepartum hemorrhage, malpresentation, oligohydramnios, anemia, major perineal tears, and an increased likelihood of cesarean delivery. To mitigate these risks, it is crucial to implement targeted community and health facility-based interventions that focus on preventing adolescent pregnancies and addressing contributing factors, ultimately improving maternal health outcomes among adolescents.