This article addresses the problem of sorting alternatives evaluated by multiple criteria among preference-ordered classes. An interactive probabilistic sorting approach is developed in which the probability of an alternative being in each class is calculated and alternatives are assigned to classes keeping the probability of incorrect assignments below a specified small threshold value. The decision maker is occasionally required to place alternatives to classes. The probabilities for unassigned alternatives are updated in light of the new information and the procedure is repeated until all alternatives are classified. This is the first sorting approach reported in the literature to use an explicit probability of classifying alternatives that is consistent with the underlying preference structure of the decision maker. The proposed approach is demonstrated in a problem concerning the sorting MBA programs.