Background: Abnormal uterine bleeding (AUB) refers to irregularities in the frequency, regularity, duration, and volume of menstrual cycles, impacting about one-third of women at some point in their lives, during menarche and perimenopausal periods. This study aims to evaluate the various causes of menstrual disorders in teenage girls. Materials and methods: This cross-sectional study was conducted in the Department of Obstetrics and Gynecology at AVMCH, Pondicherry, with ethical clearance. It included 150 girls aged 13-18 years who presented with menstrual disorders. Data were collected through structured interviews and clinical evaluations, focusing on menstrual history, socioeconomic status, associated symptoms, and investigations. Statistical analysis was performed using IBM SPSS Statistics for Windows, Version 23 (Released 2015; IBM Corp., Armonk, New York, United States). Results: Among the etiological factors, 61.3% of patients had anovulatory dysfunction, 16.6% had early onset of PCOS, 6% of patients had hypothyroidism, 16% had ovulatory dysfunction, and 0.6% had coagulation disorder. Overall, ovulatory dysfunction (AUB-O) was predominant in teenage girls. Conclusion: This study helps in the early identification of the etiology of adolescent AUB and the appropriate management of menstrual disorders to improve well-being and enhance reproductive function in the future.