Experts must often execute cognitive and motor skills in demanding, potentially stressful environments. Broadly, stress impairs attention and working memory, increasing vulnerability to cognitive overload. Theories of attentional resources and cognitive skill acquisition suggest a Standard Capacity Model (SCM) of expertise and stress vulnerability. However, the SCM has several deficiencies including neglect of contextual factors and the complexities of stress. Theoretical challenges are compounded by methodological issues including the choice of stress measure, and individual differences in response. The interplay between stress and expertise is explored across four domains: test anxiety, sports performance, surgery, and vehicle driving. In each domain, stress is sometimes associated with overload, consistent with the SCM, such that expertise buffers stressor impacts. However, expert performance is also subject to domain-specific influences beyond cognitive capacity, including strategies for emotional regulation, choking under pressure, and aggressive behaviors. Thus, relationships between stress and expertise must be understood contextually.