Background and AimBreast cancer is becoming a major public health concern globally, particularly in developing countries like Ethiopia. This study aimed to assess factors related to knowledge, attitude regarding breast cancer, and breast self-examination (BSE) practices among female preparatory students in Addis Ababa, Ethiopia.MethodsA cross-sectional study was conducted among 844 participants using a pretested self-administered questionnaire in 2021 in Addis Ababa, Ethiopia. Binary and multivariable logistic regression analyses were employed to identify factors associated with the outcome variables. A level of significance was declared based on the adjusted odds ratio (AOR) with its 95% confidence interval and p <= 0.05.ResultsOf the participants, 41.6% demonstrated good knowledge, and 47% have positive attitudes regarding breast cancer and BSE. Only, 21.9% practiced BSE regularly. Low family income (AOR = 1.791; 95% CI, 1.140-2.813) and lack of BSE awareness (AOR = 2.051; 95% CI, 1.511-2.784) were found to be associated with poor knowledge. Negative attitude was found to be significantly related to Poor knowledge (AOR = 0.713; 95% CI, 0.522-0.973) and lack of BSE awareness (AOR = 0.413; 95% CI, 0.300-0.568).ConclusionMore than half of the participants had inadequate knowledge and negative attitudes toward breast cancer and BSE, with poor BSE practice. School-based health education programs are needed to improve the participants' knowledge and attitudes.