Introduction: Women undergo menstruation as part of their normal physiological cycle. In Indian society, it is associated with taboos, myths, misbelieves and malpractice. Majority of adolescent girls are unprepared in terms of knowledge, attitude and hygienic practices for managing the menstrual cycle when they enter menarche. A better understanding of the scientific process of menstruation and good menstrual hygiene is very crucial for the health and well-being of adolescent girls. Unsafe practices are associated with unwanted outcomes. Aim: To assess the knowledge, beliefs and sources of information adolescents have about menstruation, along with their management of menstrual hygiene. Materials and Methods: The present school-based crosssectional study was conducted in 2019 in Vadodara, Gujarat, India, among 240 adolescent girls of 14-17 years of age using multistage sampling methods. Data were collected by using pre tested, structured self-administered questionnaire after having informed consent. Results: A total of 98 (40.8%) of girls were aware of menstruation before attaining menarche; 19.58% and 54.17% of girls did not knew about the cause and source of the menstrual bleeding, respectively; 55.42% girls used only sanitary pads whereas 43.33% used both old clothes and sanitary pads as the absorbents. A 46.25% changed absorbent frequently (≥4 times in a day). A 54.17% washed their genitals frequently. The most common method of absorbent disposal was disposal in a dustbin. Mother was the main source of information regarding menstruation. Conclusion: Majority of adolescent girls were not having enough knowledge regarding menstruation and their menstrual practices are inexact. This is requisite for menstrual hygiene programme.