Breast cancer is the commonest cancer among people in Sri Lanka and as well as globally. The most accessible, inexpensive, and effortless method to detect early signs of breast cancer is Breast Self-Examination (BSE). Although data revealing the knowledge, attitude, and practice of BSE on regional and global levels have become more available in recent years, the extent of knowledge, attitude, and practice of BSE among Sri Lankan teachers have not been well studied. The lack of knowledge limits the ability of public officials, health providers, and researchers to adequately address and take remedial measures to this significant health crisis. The objectives of this study were to assess the knowledge, attitude, and practice levels of BSE and to identify the association between participants' characteristics with the knowledge level.A descriptive cross-sectional study was conducted with the use of a pre-tested self-administered online questionnaire. Using Lwanga-Lemeshow equation, the sample size was calculated. A total of 275 female teachers from the government schools in the Kandy education zone, Gangawata Korale Division were assessed. Statistical analysis was done by the SPSS version 26. The data were interpreted by calculating the frequencies, and non-parametric independent sample tests were used accordingly.The study included 275 participants. Knowledge and attitudes regarding BSE of the participants were significantly associated with participants' ethnicity, religion, teaching subject/subject stream, residential area, and having a family history of breast cancer. Only one-third of the study participants had a good knowledge regarding BSE. The majority had a good attitude regarding BSE. Even though more than 90% of the study participants had heard about BSE, only 40.7% had practiced it. Though the knowledge level of the participants' regarding BSE is sufficient, there is a lack of practice among them. According to the total score given for the practice of BSE, 43.7% of the participants had good practice while a majority of 56.3% had a poor practice of BSE.Enabling education of teachers regarding breast cancer and screening in general, breast cancer complications, severity, and early detection strategies should be a priority in current efforts towards the establishment of lifelong habits like practicing BSE routinely.