The aim of this research was to investigate the role of sex, ethnicity and cognitive appraisals, separately and in combination, on the physiological stress response. One hundred and eight undergraduate students from two North Texas universities participated in the study. They were subjected to a laboratory stressor and heart rate, peripheral temperature and cortisol levels were measured pre-, during-, and post- stressor. Perceived stress and cognitive appraisals were measured via self-report. Multivariate analysis of variance tests were conducted to analyze the main and interaction effects during baseline, reactivity and post-stress recovery. Results indicated some significant main effects for sex and ethnicity but no consistent pattern of results or interactions among variables were revealed. The study's implications and areas of future research are discussed.