Educational systems are structured under multiple factors that condition and determine. Between different aspects, the time plays a key role to set the duration of each of the different educational stages and the teaching-learning process for them. Starting from this reality, this paper analyzes the school time and its influence on the academic performance, as one of the main factors in the quality of education. For this, it has been carried out a comparative study of several European countries (Finland, Austria, France and Spain) and Latin American countries (Chile, Mexico and Colombia) have participated in the Programme for International Student Assessment (PISA). From the academic results of PISA, we analyze how influences the hours of compulsory education (Primary and Secondary) in student performance. Between the results obtained, we can stand out that simply increasing the number of hours in the different educational stages no positive effect in student 12 E. Colomo, A. Cívico, V. Gabarda y N. Cuevas © SECRETARIADO DE PUBLICACIONES UNIVERSIDAD DE SEVILLA performance. Inversely, becomes more important the way of approach the teaching-learning process (whatever we as professional education in the classroom) that the time used in it.