Student’s room allocation is a challenging problem. Our aim is to develop a methodology as well as a Decision Support System for allocation students’ rooms considering several criteria and several aggregation methodologies. For this article we used the multi-criteria decision-making methods like “Analytic Hierarchy Process” (AHP), “Weighted Sum Method” (WSM), “Technique for Order Preference by Similarity to the Ideal Solution” (TOPSIS) and “Combined Compromise Solution” (CoCoSo) to solve the problem of allocation of student accommodation. The contributions of these methods were as follows: AHP to rank criteria weights, WSM, TOPSIS and CoCoSo to rank students. We found that the ranking results of the students from each method are different because each of these methods has its specificity. In relation to this situation, we checked the similarity of the ranks obtained by applying two tests of the rank correlation coefficients, such as Spearman’s coefficient and Kendall’s coefficient. Thus, these tests showed us that ranks tend to be positively correlated for both test scores. As the correlation was proven, we retrieved these ranks and reordered the students to obtain a compromised ranking through an aggregating decision-making method that we called the “Minimum of ranks” (MIRA). To validate this method, we also checked the similarity of the ranks which has just been obtained compared to those of the WSM, TOPSIS and CoCoSo methods. The test carried out by the coefficients of the ranks of Spearman and Kendall gave us a positive correlation of the ranks. The MIRA process will be presented in this article. Finally, a decision support system (DSS) based on the AHP, WSM, TOPSIS, CoCoSo and MIRA methods was developed to solve the problem of student’s room allocation.