Abstract  We review work relating glucocorticoids (GCs), male sexual signals, and mate choice by females to
understand the potential for GCs to modulate the expression of sexually selected traits and how sexual
selection potentially feeds back on GC regulation. Our review reveals that the relationship between GC
concentrations and the quality of male sexual traits is mixed, regardless of whether studies focused on
structural traits (e.g., coloration) or behavioral traits (e.g., vocalizations) or were examined in
developmental or activational frameworks. In contrast, the few mate choice experiments that have been
done consistently show that females prefer males with low GCs, suggesting that mate choice by females
favors males that maintain low levels of GCs. We point out, however, that just as sexual selection can
drive the evolution of diverse reproductive strategies, it may also promote diversity in GC regulation. We
then shift the focus to females where we highlight evidence indicating that stressors or high GCs can
dampen female sexual proceptivity and the strength of preferences for male courtship signals. Hence,
even in cases where GCs are tightly coupled with male sexual signals, the strength of sexual selection on
aspects of GC physiology can vary depending on the endocrine status of females. Studies examining how
GCs relate to sexual selection may shed light on how variation in stress physiology, sexual signals, and
mate choice are maintained in natural populations and may be important in understanding context-
dependent relationships between GC regulation and fitness.