impulsive responses to ultimatums may cause rejection of unfair offers at a cost to oneself. A possible ameliorating strategy is self-regulation by setting goals and making plans geared toward controlling impulsive responses that may lead to rejection. Two studies test the hypothesis that entering an ultimatum with specific goals and plans (i.e., implementation intentions) will lead to increased acceptances of ultimatums that are unfair but more profitable than rejection. in Experiment 1 participants with a goal intention to stay calm accepted unfair ultimatums more than participants who were not given such a goal. in Experiment 2, we studied participants’ reactions to ultimatums that were harder to accept, and found that goal intentions supported with implementation intentions (if–then plans) significantly increased the chance of acceptance, compared with having only goal intentions. implications of these findings for self-regulation in ultimatum bargaining are discussed.