The role of a practicing psychologist often involves uncertainty and ambiguity, and individuals differ in their ability to manage or “tolerate” this uncertainty. This study investigated the relationship between tolerance of uncertainty, pluralism and confidence in case formulation in a sample of Australian psychologists. The sample consisted of 190 Australian psychologists, aged between 22 and 69 years (M = 30.48, SD = 8.04) and comprising mostly females (77.9%). This study had a cross-sectional survey design in which participants completed measures of uncertainty tolerance, pluralism and confidence in case formulation. Hierarchical multiple regression was used to predict tolerance to uncertainty. The final regression model was significant and explained 39.1% of the variance in tolerance of uncertainty. The predictor variables that contributed significantly to the model were therapeutic orientation, age, pluralistic practice and confidence in case formulation. Stage of career and pluralistic philosophy did not contribute significantly to the model. Higher pluralistic practice and confidence in case formulation skills are related to higher tolerance of uncertainty. Training in pluralistic models of therapy and the hypothesis generation approach to case formulation may offer the potential to increase uncertainty tolerance in practicing psychologists.