Cognitive dysfunction following breast cancer treatment is a serious and pervasive problem. The underlying mechanisms of cancer related cognitive impairments remain unclear, but there is consensus within the scientific community that the causes are multifactorial. This non-experimental, cross-sectional study is an analysis of data from 75 breast cancer survivors six months to 10 years post chemotherapy. The purpose of this study was to identify modifiable psychosocial and behavioral factors that may contribute to cognitive function both directly and indirectly through inflammatory mediators. Non-linear regression models were used to determine whether stress, perceived social isolation, physical activity, sleep quality, and inflammation are significant predictors of cognitive function. Hierarchical multiple regression was used to determine the unique variance of cognitive function (perceived and performance) explained by the predictor variables. Non-parametric regression was used to illustrate the complex relationships between the psychosocial and behavioral factors and cytokines, and between the cytokines and cognitive outcomes. Mediation analyses were used to gain a better understanding of how the psychosocial variables influence perceived cognitive function. The findings from this study suggest that perceived stress and loneliness contribute to perceived cognitive functioning in breast cancer survivors but that elevated IL-6 and TNF-α do not mediate these effects. Non-parametric regression graphing illustrated that the cytokines were related to the predictor variables and that cognitive outcomes were related to the cytokines but that the relationships varied in direction and magnitude across levels. This study provides new knowledge on inflammation and cognitive function six months to 10 years after breast cancer chemotherapy using a biobehavioral model to simultaneously evaluate modifiable psychosocial and behavioral factors that contribute to cognitive function in breast cancer survivors. Findings from this study provide initial evidence for needed future prospective and translational studies to improve cognitive function in breast cancer survivors