There are reports of low utilization of contraception among adolescent females in developing countries. However, research on sexual behaviour and contraceptive uptake among female adolescents is scare in the Sagnarigu Municipality although the Municipality has a very high youthful population. The objective of the study was to assess the sexual behaviour and contraceptive uptake among adolescent females in Sagnarigu Municipality, Northern Region, Ghana. A cross-sectional study was adopted where 165 adolescent females (15-19 years) were randomly selected. The main tools for data collection were semi-structured questionnaires. For the data analysis, proportions of response variables were generated using statistical product and service solutions, version 24.0. The study revealed that among those who reported having sex in the past 12 months before the survey, over two-thirds of the participants have used at least one method of contraception. The results also showed that injectable was the leading form of contraception among both past and current users of contraceptive methods. Additionally, most of the respondents obtained their contraceptive methods from health facilities. We also established that avoidance of pregnancies was the main reason for using contraception. However, cultural beliefs, religion, fear of side effects were the reasons for non-use of contraceptives. The study further revealed that early initiation of sex among the participants was common. Nevertheless, some of the participants did not use contraceptives during sexual intercourse. The study recommended effective education on the types and uses of contraceptives among adolescents in the municipality.