Access to sexual and reproductive health information and services among the young people remains a highly contested issue in many traditional societies Zambia included. Access to youth-friendly health services such as contraceptives is vital for ensuring the well-being of adolescents. This study endeavoured to establish determinants of contraceptive use among teenage girls aged 15 to 19 years in Eastern Province, Zambia. This was a mixed methods study that employed a sequential explanatory design. In the quantitative arm, the study utilized the 2018 Zambia Demographic and Health Survey (ZDHS) women's dataset for Eastern Province, focusing on 326 teenage girls aged 15-19 years. The ZDHS data collection was done using multiple cluster sampling method and through household survey. The qualitative arm involved 6 focus group discussions with parents, 4 interviews with teachers and 6 interviews with healthcare providers in Petauke district. Contraceptive prevalence rate, and socio-economic and demographic factors influencing contraceptive use were measured in the quantitative part. The perception on teenage contraceptive use among key influencers was assessed in the qualitative arm. The prevalence of contraceptive use among teenage girls in Eastern province was at16%. Age, marital status, parity, visiting a health facility, being visited by a health provider and hearing about family planning on radio were significantly associated with contraceptive use (p< 0.05). Moreover, teenage girls who had ever been married had higher odds of contraceptive use than unmarried ones (AOR 3.57, 95% CI, 1.59, 8.01, p = 0.002). Further, those who heard about family planning at the health facility (AOR 2.37, 95% CI, 1.08, 5.21, p = 0.031) and those who heard on radio (AOR 2.55, 95% CI, 1.05-6.19, p = 0.038) had higher odds of contraceptive use than those who did not. The qualitative results found that most parents and teachers opposed the use of contraceptive by teenagers, while health providers supported it. Barriers to contraceptive use included religious beliefs, personal beliefs of healthcare providers, myths and misconceptions, and the fear of social stigma by teenagers. Whether or not adolescents have access to contraceptives, the decision to use them is heavily influenced by parents, and to some extent, teachers and health providers. Therefore, it is important to implement comprehensive educational programs not only for teenagers, but also for parents, teachers and healthcare providers, dispelling myths about contraceptives.