This paper derives hypotheses on how dyadic social support is affected by heterogeneity of the actors. We distinguish heterogeneity with respect to three parameters. First, the likelihood of needing support; second, the benefits from support relative to the costs for providing support; and, third, time preferences. The hypotheses are based on a game theoretic analysis of an iterated Support Game. We predict that, given homogeneity in two of these parameters, the prospect for mutual support is optimal if actors are homogeneous with respect to the third parameter as well. Second, under heterogeneity with respect to two of the parameters, support is most likely if there is a specific heterogeneous distribution with respect to the other parameter that ‘compensates’ for the original heterogeneity. Third, under weak conditions, the overall optimal condition for mutual support is full homogeneity of the actors.