Autobiographical and clinical accounts of individuals with autism spectrum disorder (ASD) have highlighted that these individuals experience several difficulties during the decision making process. A review of the experimental based studies assessing performance in decision making tasks compared to controls emphasizes key differences including altered risk preferences, decreased sensitivity to social rewards, increased deliberative reasoning and atypical integration of emotional cues. Despite several attempts to devise cognitive theories to explain these differences, none so far can account for all the differences seen. However, one key observation, consistent with clinical accounts, is elevated levels of anxiety in populations with ASD. Whilst this has traditionally been considered a bi-product of the decision making process, I argue that increased anxiety may directly influence decision making in individuals with ASD, through 2 main routes. Firstly, elevated anxiety overwhelms Type 1 (intuitive) fast processes (within the Dual Process Model), leading to a decision making style biased by Type 2 (deliberative) processes. In addition, heightened anxiety decreases cognitive flexibility, leading to a more logic based, deliberative decision making style. This is superimposed on pre-existing cognitive impairments which altogether may account for the differences seen. Therefore, anxiety must be considered as a key variable in cognitive models of decision making in ASD. Specific recommendations for future research exploring the role of anxiety are discussed.