The article aims to understand the limits and perspectives relating to the initial training and working conditions of High School teachers in Brazil. It presents a discussion based on educational indicators related to the valorization of High School teachers, highlighting Appropriate Teacher training and Teaching Effort. The data express limits related to the proposed goals 15 to 18 of the National Education Plan (2014-2024), and evidence challenges to increasing academic training and improving working conditions for High School teachers. This study points to a need to increase the number of teachers with appropriate training in state High Schools from around 58% at present, to 100%. The study indicates that about 25% of teachers have more than 300 students, and that they work in three shifts, in two or three schools, and in two or more levels of education. It is suggested that the quality problem in High School education, which was discussed with great intensity after the sanction of Law 13.415/2017, will not be resolved by the proposed curricular flexibilization. The resolution demands, besides curriculum changes, initial and continuing training for teachers, remuneration, and career and working conditions consistent with their professional practice, ensuring a school with quality for all.