TIMSS is an internationally applied instrument for measuring trends in Mathematics and Science achievement in the fourth grade of primary and eighth grade of secondary school. Given the design of these tests, it is possible to obtain traceable and comparable results, which allow governments of different nations to generate, maintain or eliminate public policies with the objective of improving their education system. Naturally, these tests have acquired great relevance at the global level. Considering the above, the objective of this academic work is to propose an estimator using Small Area Estimation that allows for improving the quality of the estimates currently obtained with the sampling design used in TIMSS 2015. In addition, this methodology allows us to estimate the result that would have been obtained by a country that did not present this test in 2015, but has auxiliary information related to academic achievement. To build the estimator of academic achievement, the Fay-Herriot model is used using auxiliary variables such as demographic and socioeconomic information and scores obtained in previous applications of the test. Finally, this paper will show that the use of Small Area Estimation in international tests improves the efficiency of the results obtained and, therefore, allows for better decision-making in education policy.