Lay third parties sometimes react to an interpersonal dispute by taking sides. In this paper, we investigate the interaction effects of lay third parties' moral and expedient orientations on the relationship between perceived legitimacy (or expected negative sanctions) and their intention of side-taking with a legitimacy party (or a sanction party). Seventy-nine Chinese and 77 Dutch employees were presented with a scenario describing a conflict dilemma between one party who has more legitimacy claims but less negative sanctions and the other party who has less legitimacy claims but more negative sanctions. The results showed that moral orientation by itself has a reinforcing effect on the positive link between perceived legitimacy and siding with a legitimacy party. In addition, in both countries, the relationship between expected negative sanctions and side-taking with a sanction party was moderated by a joint effect of the moral and the expedient orientations. That is, for lay third parties with a weakly moral orientation and a strongly expedient orientation, an increase in negative sanctions led to more side-taking with a sanction party. For those lay third parties who were weakly moral and weakly expedient oriented, strongly moral and strongly expedient oriented, or strongly moral and weakly expedient oriented, the above-mentioned link was not positive any more.