Individuals with a history of poor interpersonal relationships are more likely to demonstrate negative health outcomes than those who have had high quality relationships. We sought to evaluate how attachment orientations, stress-induced respiratory sinus arrhythmia (RSA), and self-reported stress were associated with length of telomeres measured from peripheral blood mononuclear cells. Participants (N = 213) completed self-report measures of attachment and stress. Measurement of RSA was conducted before and after a stressful task and a blood draw was completed for analysis of telomere length. Attachment orientations were not directly associated with telomere length; however, we found that high attachment anxiety was associated with shorter length of telomeres via high self-reported stress. Attachment avoidance was also associated with telomere length via self-reported stress, but only among those with high stress-induced RSA. Exploratory analyses of T cell subsets indicated that stress was most strongly associated with telomeres from CD8CD28+ cells in comparison to CD8CD28− and CD4 cells. Study findings indicate that attachment orientations are associated with telomere length via stress, providing novel insights into the mechanisms through which close relationships can impact health and aging.