© 2021 British Association of Urological Nurses and John Wiley & Sons Ltd.Do male high school students know about testicular cancer and testicular self-examination (TSE)? Testicular cancer (TC) is increasing among young men, who demonstrate a lack of knowledge about TC and TSE. The aim of this research was to state the knowledge and attitudes regarding TC and the practice of TSE among male high school students. The assessment of the literature addressing high school students' knowledge regarding TC and TSE has shown a common lack of awareness and knowledge about this disease. Moreover, very few males perform TSE. This descriptive, cross-sectional study was conducted in May and October 2019 with 1343 male students aged 14–21 years from six different high schools in Turkey. The survey consisted of knowledge, attitudes and awareness regarding TC and TSE. A survey was performed immediately before the end of student courses and again during courses after the start of the next school year. Data from all six schools were collected in a common database. The survey showed that 58.2% of the participants had never heard of TC and 85.8% had never heard of TSE. Additionally, 84.3% of the participants did not perform TSE, and 85% did not know how to perform TSE. The present study found that knowledge regarding TC and the performance of TSE was weak among high school students. Concerning students' attitudes, 85.6% of the students reported that testicular cancer is a severe disease, and 82.1% of the students reported that TSE is significant for the early detection of this disease. These findings indicate that students have very little information about TC and TSE. It would be useful to provide TC and TSE training for health professionals. Good knowledge and awareness regarding TC are associated with performing TSE.