Background <p>Poor sleep quality is linked to increased risk for cardiometabolic complications and mortality. Previous research suggested workplace and everyday discrimination are separately linked to adverse sleep outcomes. The aim of this study is to examine the joint effects of workplace and everyday discrimination on sleep quality among middle-aged adults.</p> Methods <p>Data from the Midlife in the United States (MIDUS) study were used, with a 9-year follow-up of 1,333 individuals free from sleep disturbances at baseline. Baseline measures of workplace and everyday discrimination were collected, and the incidence of sleep disturbances was assessed at follow-up. Poisson regression was used to estimate risk ratios (RRs) and 95% confidence intervals (CIs). The synergy index was applied to evaluate whether the combined effect of both types of discrimination was greater than their individual effects.</p> Results <p>Workplace discrimination was associated with a higher risk of sleep disturbances (adjusted RR = 1.50 [1.09, 2.06]). Everyday discrimination also increased the risk of sleep disturbances (adjusted RR=&#xa0;1.38 [1.00, 1.93]). The joint effect of workplace and everyday discrimination was associated with a higher risk of sleep disturbances (adjusted RR = 1.78 [1.16, 2.72]), with synergy index suggesting an additive interaction.</p> Conclusion <p>Both workplace and everyday discrimination independently affect sleep quality, with an additive interaction between the two. The double burden of workplace and everyday discrimination can significantly impact sleep disturbances. Further research is needed to explore the biological mechanisms linking discrimination and sleep disturbances.</p>