In a k-player, nonzero-sum differential game there exists the possibility that a group of players will form a coalition and work together. If all k players form the coalition, the criterion usually chosen is Pareto optimality, whereas if the coalition consists of only one player, a minmax or Nash equilibrium solution is sought. In this paper, games with coalitions of more than one but less than k players are considered. Coalitive Pareto optimality is chosen as the criterion. Sufficient conditions are presented for coalitive Paretooptimal solutions and the results are illustrated with an example.