1. Short-term elevations in circulating stress hormones (glucocorticoids) often mediate reduced investment in reproductive behavior in favor of self-maintenance and survival, but the significance of these effects in sexual selection and communication remain largely unexplored. 2. Here we examine the acute stress response in the context of intra- and intersexual selection in the green treefrog, Hyla cinerea. Males of this species produce agonistic acoustic signals that stimulate elevations in the stress hormone corticosterone (CORT) in rival males, suggesting a central role for CORT in male-male competition. We hypothesized that elevated CORT levels in losers of vocal contests mediate an increase in the energy allocated towards self-maintenance and survival that compromises investment in courtship signaling, resulting in reduced attractiveness to females. 3. Consistent with this hypothesis, we show that CORT administration to calling males, simulating CORT production in vocal contest losers, caused a rapid reduction in the duration of advertisement calls and vocal effort. Elevated CORT also increased the propensity to produce aggressive calls during simulated territorial intrusions that was followed by an increased probability of non-calling “satellite” mating behavior. This suite of CORT effects on vocal behavior are known to decrease attractiveness to females and were not related to a decrease in androgen level or differences in body condition in CORT- versus saline-injected males. 4. Our results suggest that CORT production during intraspecific vocal contests compromises male attractiveness. Male vocalizations may therefore reliably indicate recent contest outcomes and/or the stress status of males, implicating CORT as a mediator of honest signaling. We propose that the effects of agonistic acoustic signals on CORT production in this species are maintained by CORT-mediated life history trade-offs; decreased conspicuous signaling in high stress-responsive males potentially increases survival by reducing the likelihood of escalated contests with dominant males and detection by predators. Adoption of alternative non-calling satellite mating tactics may contribute to maintaining individual variation in stress responsiveness by increasing the chances that competitively inferior males acquire mates.