Low contraceptive use in sub-Saharan Africa, and Zambia specifically, negates the potential benefits of contraception in preventing unwanted and early pregnancies. This study aimed to explore and understand the motivators and influencers of adolescent girls’ contraceptive decision making. Using thematic analysis, we analysed qualitative data from seven focus group discussions and three key informant interviews with adolescent girls aged 15 to 19 years in four Zambian districts. The data were managed and organised using NVivo version 12 pro (QSR International). Fear of pregnancy, fear of diseases, fear of having more children, and spacing of children (especially among married adolescents) were key motivators for adolescents’ contraceptive use. Friends and peers motivated them to use contraceptives while fear of side effects and fear of infertility drove non-use. Peer pressure and fear of mocking by their friends were important deterrents to contraceptive use. Parents, peers and friends, family members, partners, churches, and religious groups influenced adolescent girls’ contraceptive decisions. Mixed messages from these influencers, with some in favour and others against contraceptives, make adolescents’ decisions to use contraceptives complex. Therefore, interventions targeting increased contraceptive use should be all-inclusive, incorporating multiple influencers, including at institutional and policy levels, to empower adolescents and give them autonomy to make contraceptive decisions.