INTRODUCTION Teenage pregnancy is associated with poor maternal and perinatal health outcomes, and also has a major social and economic impact. Its magnitude and determinants in Ethiopia are not well understood, therefore the aim of this study was to assess the prevalence and associated factors of teenage pregnancy among teenagers in northwest, Ethiopia, 2020. METHODS A community-based cross-sectional study was conducted among 343 teenagers from 15 February 2020 to 24 March 2020. Multistage sampling technique was used to select study participants. Data were collected using a structured and pretested questionnaire. Bivariable and multivariable logistic regression models were fitted to identify factors associated with teenage pregnancy. RESULTS The prevalence of teenage pregnancy among respondents in Farta woreda was 25.4% (95% CI: 21.3-30.3). Residence (AOR=0.46; 95% CI: 0.11-0.80), early age at 1st sexual intercourse (AOR=1.68; 95% CI: 1.57-4.21), not knowing family planning methods (AOR=2.14; 95% CI: 1.54-2.54), not utilizing contraception (AOR=2.31; 95% CI: 1.06-4.99) and did not know a place where contraceptive methods are provided (AOR=3.46; 95% CI: 1.89-11.06) have significant association with teenage pregnancy. CONCLUSIONS Residence, early age at 1st sexual intercourse, not knowing family planning methods, not utilizing contraception and not being aware of a place where contraceptive methods are provided were associated with teenage pregnancy. The creation of awareness for the timing of safe sexual intercourse, the types and locations where family planning methods are available, and the promotion of family planning use for postponing pregnancy, should be taken into account within family planning.