Attitudes to uncertainty describe perceptions of uncertaintyUncertainty and affect an individual’s reaction to it, taking similar concepts such as ambiguityAmbiguity and risk into account. This chapter looks at the associations between these, and intolerance of uncertaintyIntolerance of uncertainty in particular, with a variety of decision outcomesDecision outcomes. It first presents the main approaches to uncertainty and how it is perceived. The central part of the chapter is divided into four sections, which explore the decisional outcomes of attitudes to uncertainty in information processingInformation processing, psychological disordersPsychological disorders, well-beingWell-being, and real life. The closing section presents the main conclusions and challenges for futureFuture risk research.