Knowledge regarding reproductive health among adolescent girls is very essential to lead healthy lives and protect themselves from reproductive health problems. Main objective of the study is to assess the knowledge about reproductive health among adolescent high school girls. Materials and Methods: It was a descriptive cross-sectional study conducted among one hundred and twenty adolescent girls in a high school located in rural area. A pre-designed, pre-tested questionnaire was used. Data on knowledge regarding pubertal changes, menstruation, legal age at marriage, conception, HIV/AIDS was collected. Data obtained were analyzed statistically by simple proportions using Micro-soft Excel. Results: Mean age of adolescent girls was 13.6±0.85yrs and their mean age at menarache was 11.5±3.7yrs. More than half of girls had knowledge about pubertal changes but only 14.2% of the girls knew that uterus is the organ responsible for menstruation. Knowledge regarding menstrual hygiene was poor. Majority had idea about legal age for marriage as 18 years. More than half of them said that uterus as site of fetal growth. More than 80% heard about HIV/AIDS but only 30% had knowledge about routes of spread. Conclusion: knowledge about reproductive health among study subjects was observed to be patchy and necessary health education is greatly needed.