Background: Developmentally appropriate evidence-based sexual health education should be included as part of a comprehensive school health education program and be accessible to all students. The registered school nurse is a valuable resource to parents and educators in this area and supports the implementation of evidence-based sexual health education programs that promote healthy sexual development for adolescents. Methods: The research group consisted of 438 adolescents aged 12 to 15 years in a selected region in Slovakia, 186 boys and 252 girls. Average age of the girls was 13.2 and the boys 13.3 years. A nurse—a specialist in community nursing—collected the data using a self-designed questionnaire. The questions evaluated by the five-point Likert scale focused on finding out the knowledge and attitudes of adolescents to the role of school nurses regarding sexuality and reproductive health. Results were analyzed using parametric comparison tests with significance value 0.05: Student t-test for independent samples. Results: The girls and the boys most often drew information on sexuality and reproductive health from their parents and friends. The evaluation of the adolescents’ views on who should be a competent professional in the field of sexual education at schools found statistically significant differences between the boys and girls. For the boys and girls, a sexologist received the most significant assessment of competence. The interest in a school nurse in a school environment would be statistically significantly more appreciated by the girls compared to the boys, not just for solving problems related to healthy lifestyle, but also regarding sexuality, parenting and marriage. The adolescents consider the education for marriage and parenthood as the least discussed issue at present. In evaluating topics the adolescents would discuss, there were statistically significant differences between the boys and girls. Conclusions: A community or school nurse would also be able to successfully perform sexual education at schools. In Slovakia, this applied nursing discipline is lacking.