Examining the multitude of influences on the development of adolescent stress responses, especially among low-income families, is a critical and understudied topic in the field. The current study examined cortisol attunement between adolescent girls and parents (mostly mothers) from predominantly low-income, single parent, ethnic minority families before and after an in-laboratory disagreement discussion task. The sample consisted of 118 adolescents (Mage = 13.79 years, 76.3% ethnic minorities, 23.7% European Americans) and primary caregivers (Mage = 40.62 years; Mdn yearly income = $24,000; 43.2% single parents; 50% living below poverty line). We investigated oxytocin receptor (OXTR rs53576) gene variations as a potential contributor to attunement within the dyad. Results showed that parents and adolescents showed stress system attunement across the disagreement task, but that parent and adolescent oxytocin receptor genotype did not impact attunement. Future studies should detail biological factors that contribute to the calibration of stress response systems of adolescents across a variety of samples, particularly those experiencing a combination of stressors