Revealing one's sexual identity to others is a complex process marked by a shift in the types of stressors faced by sexual minority young adults. Such stressors influence the secretion of health-relevant hormones, including cortisol, yet how dimensions of disclosure (i.e., the degree and context) influence neuroendocrine functioning remains poorly understood. The current study examined the association between disclosure context (disclosure to family members, friends/co-workers/acquaintances, and members of religious groups) and diurnal cortisol while allowing disclosure to vary in degree (i.e., how much is disclosed). One hundred twenty-one sexual minority young adults (aged 18-35 years, 54.5% female, free of major psychiatric/endocrine disorders) completed an initial survey that assessed the degree and context of sexual minority identity disclosure. A randomly selected subset (n = 58) also provided salivary cortisol samples at wake, 45 minutes after wake, 12 hours after wake, and at bedtime for 1 week. Greater total disclosure and greater disclosure to family members were associated with reduced cortisol output, defined as Area Under the Curve relative to ground (AUCg; F(1,230) = 5.95, p = .015, and F(1,231) = 10.90, p = .001, respectively). Disclosure to co-workers, friends, acquaintances, or religious groups was unrelated to cortisol AUCg. All disclosure contexts tested were unrelated to the shape of diurnal cortisol slopes (including the cortisol awakening response). Disclosure to family members uniquely predicted cortisol AUCg. Therefore, these results suggest that effects of disclosure on diurnal cortisol and its associated health outcomes may occur in the context of familial relationships.