Active pedagogies and specifically cooperative learning have been described as effective tools for inclusion and educational equity, a key concept in objective 4 within the Sustainable Development Goals. The aim of this study was to test the temporal stability of a cooperative learning (CL) over two academic years and to analyse its effects on achievement in mathematics. The sample consisted of 6456 students enrolled in school in Spain, aged between 10 and 15 years. The results showed some consistency in the use of this methodology during two school years. Mathematics scores correlated positively with all elements of CL in each of the separate school years. However, logistic regression data showed a significant drop in mathematics. In contrast, during the same period, four of the five elements of CL correlated positively with the results.