Most children born with even the most critical forms of CHD are now surviving well into adulthood. However, with increased survival has come increased recognition of the diverse neurobehavioural and psychosocial challenges these children experience. Among these challenges are deficits in executive function skills, including inhibitory control, working memory, and cognitive flexibility. Over the past several years, whereas inhibitory control and working memory deficits have garnered particular attention among clinicians and interventionists, relatively less attention has been paid to cognitive flexibility. This is unfortunate given both the high prevalence of cognitive flexibility deficits observed in children and adolescents with critical CHD, and also the far-reaching relevance of cognitive flexibility in helping individuals achieve optimal quality of life across the lifespan. This paper reviews the construct of cognitive flexibility, including its definition, development, measurement, and neuroanatomical basis, provides a summary of how cognitive flexibility is affected by CHD, and offers evidence-based recommendations to systematically support the development of cognitive flexibility within the context of CHD.