Background: In Mozambique, 76% of adolescents have been pregnant before the age of 20 years. Thus, this study explores adults’ perceptions on adolescent attitudes towards pregnancy and abortion in Maputo and Quelimane cities. Methods: A qualitative study was conducted in Maputo and Quelimane, with four focus group discussions. A cross-sectional household survey was used to select adult women participants. Data were analysed applying a thematic analysis approach. Results: Intrapersonal, interpersonal, cultural, and environmental factors influence pregnancy and abortion decision making among adolescents. Generational conflicts reduce the importance paid to traditional knowledge transfer, contraceptive beliefs, denial of paternity, lack of parental support, and procreation value were found to influence abortion decision making and early pregnancy among adolescents. Conclusions: There is a need to improve relationships between adults and adolescents to reduce girls’ vulnerability to early pregnancy, as well as empowering adolescents in order to negotiate safe sex, reducing unwanted pregnancy and induced abortion.