Background: Clinical reasoning, which refers to the application of critical thinking in themedical field, is currently extensively studied in order to find out how to make properdiagnoses. Literature indicates that Intolerance of uncertainty (IU) may have a strong impacton clinical reasoning, and this review aims at summarizing the various consequences of IUon clinical reasoning.Methods: A systematic review was conducted using relevant keywords to search databases(i.e., Google Scholar, Medline, PsycINFO, PBSC) from September to November 2021.Complementary research included relevant articles and articles retrieved through GoogleScholar's alert system.Findings: Our initial search yielded 1853 articles, of which 8 were included in our finalsample. Two behavior categories were affected: investigative and prescriptive behaviors.Regarding the investigation process, mismanagement of uncertainty appeared to lead to reasoning bias, potentially resulting in diagnostic errors. IU was associated with withholding information, more referrals to peers and less use of new medical interventions. Regarding prescription behaviors, IU among health professionals could lead to overprescribingunnecessary or dangerous tests. IU was also associated with more antibiotic prescriptionsfor conditions where antibiotics are to be used carefully. IU could also influence abortion recommendation. Discussion: Few studies have yet addressed the impact of IU on clinical reasoning. IU'sinfluence is primarily observed on investigative and prescribing behaviors. More studies arestill needed to fully understand the impact of IU on clinical reasoning itself, and not only onpractical consequences.