Studies have suggested a potential link between traumatic experiences, psychological stress, and autoimmunity, but the impact of stress on disease activity and symptom severity in systemic lupus erythematosus (SLE) remains unclear. The present study was undertaken to examine whether increases in perceived stress independently associate with worse SLE disease outcomes over 3 years of follow-up. Participants were drawn from the California Lupus Epidemiology Study (CLUES). Stress was measured annually using the 4-item Perceived Stress Scale (PSS). Participants with increases of ≥0.5 SD in PSS score were defined as having an increase in stress. Four outcomes were measured at the year 3 follow-up visit: physician-assessed disease activity (Systemic Lupus Erythematosus Disease Activity Index); patient-reported disease activity (Systemic Lupus Activity Questionnaire); pain (Patient-Reported Outcomes Measurement Information System [PROMIS] pain interference scale); and fatigue (PROMIS fatigue scale). Multivariable linear regression evaluated longitudinal associations of increase in stress with all 4 outcomes while controlling for potential confounders. The sample (n=260) was 91% female, 36% Asian, 30% White, 22% Hispanic, and 11% African American; the mean ± SD age was 46 ± 14 years. In adjusted longitudinal analyses, increase in stress was independently associated with greater physician-assessed disease activity (P=0.015), greater self-reported disease activity (P < 0.001), more pain (P=0.019), and more fatigue (P < 0.001). In a racially diverse sample of individuals with SLE, those who experienced an increase in stress had significantly worse disease activity and greater symptom burden at follow-up compared to those with stress levels that remained stable or declined. Findings underscore the need for interventions to bolster stress resilience and support effective coping strategies among individuals living with lupus.