Chronic stress is an important predictor of mental and physical health, but little is known about its association with cognitive abilities and education during the lifespan. We hypothesized that chronic stress would be negatively correlated with cognitive abilities, particularly crystallized intelligence, and that this association would be stronger among individuals with lower educational attainment due to limited stress-coping resources. We used cross-sectional data from the German National Educational Panel Study (NEPS SC6), comprising 10,416 adults aged 29 to 71 years (50.80% female; 49.20% male). Fluid and crystallized intelligence were assessed with a reasoning test and a vocabulary test, respectively; chronic stress was assessed with a questionnaire on social stress and anxiety. The tests and the questionnaire were conceptualized for a heterogeneous and large-scale sample. Our results show small negative associations between chronic stress and both fluid and crystallized cognitive abilities, which persist after controlling for demographic variables. However, there were no significant differences between educational groups. Although the study does not address longitudinal patterns, it highlights the complex interaction between stress and cognition, and it underscores the need for further research to explore how educational resources may mitigate the impact of chronic stress on cognitive health.