This article presents two studies examining the impact of procedural fairness, outcome favorability and outcome fairness on the acceptance of tax authority decisions. Twofactor experimental studies were conducted using a sample of 198 people: 2 x procedure (fair vs. unfair) and 2 x outcome favorability or outcome fairness. Study 1 found no procedural fairness effect, level of tax decision acceptance being dependent only on outcome favorability. Respondents accepted personally favorable decisions more even when they resulted from an unfair procedure. The fair process effect was only related to outcome fairness, higher acceptance of tax decisions resulting from fair procedures regardless of their consequences. Results suggest outcome favorability has a stronger influence than outcome fairness.