Widow(er)s experience significant sleep disruption that may dysregulate immune functioning. This longitudinal study aimed to determine 1) whether changes in sleep quality were associated with changes in pro-inflammatory cytokine production during the first six months of bereavement and 2) whether these relationships depended on objective socioeconomic status (SES) and/or subjective social status. One hundred and six bereaved spouses (M ​= ​68.49 years, SD ​= ​9.35, 69 females) completed the following assessments at approximately three months post-death and six-month post-death: a venous blood draw and self-report questionnaires on sleep quality (Pittsburgh Sleep Quality Index), SES (MacArthur Sociodemographic Questionnaire), health, and demographic information. T-cell stimulated pro-inflammatory cytokines were assessed, including IL-6, TNF-α, IFN-γ, IL-17A, and IL-2. Worsening sleep quality was associated with increased levels of pro-inflammatory activity even after adjusting for confounding variables. The present study also identified SES as an important factor for understanding health following spousal bereavement: individuals with low SES were more susceptible to sleep-related changes in immune function. Compared to more educated widow(er)s, less educated widow(er)s showed greater increases and decreases in inflammation when sleep quality worsened or improved, respectively, over time. Findings provide evidence for a biobehavioral pathway linking bereavement to disease risk, highlight SES disparities in late adulthood, and identify individuals who may require tailored interventions to offset SES-related burden that impedes adaptive grief recovery.