Objective This study examined cross‐sectional and longitudinal relationships between educational attainment and psychiatric disorders (i.e., mood, anxiety, substance use, and personality disorders) using a nationally representative survey of US adults. Method We used data from Waves 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (N = 34,653). Bivariate and multiple logistic regressions examined cross‐sectional and longitudinal associations between educational attainment and a variety of past‐year and incident anxiety, mood, and substance use disorders, controlling for sociodemographics and psychiatric disorder comorbidity. Results Adjusted cross‐sectional data indicated that educational attainment below a graduate or professional degree at Wave 2 was associated with significantly higher odds of substance use and/or dependence disorders (adjusted odds ratio range (AORR = 1.55–2.55, P < 0.001). Longitudinal adjusted regression analyses indicated that individuals reporting less than a college education at Wave 1 were at significantly higher odds of experiencing any incident mood (AORR 1.49–1.64, P < 0.01), anxiety (AORR 1.35–1.69, P < 0.01), and substance use disorder (AORR 1.50–2.02, P < 0.01) at Wave 2 even after controlling for other sociodemographic variables and psychiatric comorbidity. Conclusion Findings lend support to other published research demonstrating that educational attainment is protective against developing a spectrum of psychiatric disorders. Mechanisms underlying this relationship are speculative and in need of additional research.