In clinical trials of drug treatments for women’s sexual dysfunction, placebo responses have often been substantial. Little is known about the nature and time course of symptom reduction with placebo treatment. It is also unknown to what extent placebo responses might be associated with individual characteristics, such as demographic variables, that influence responsiveness to treatment. Finally, it is unknown how sexual behavior during placebo treatment changes and whether changes in sexual behavior account for variability in outcomes. In the present work I investigated potential between-trial, between-person, and within-person variables that might explain variability in response to placebo treatment of sexual dysfunction in women. Study 1 consisted of a systematic review of the clinical trial literature to estimate the magnitude and predictors of placebo response across previous trials. Study 2 was an analysis of a small sample of women who were randomized to receive placebo in a recent clinical trial. These preliminary studies provided evidence of a relatively large clinical response among women randomized to placebo in controlled clinical trials of sexual dysfunction treatments. In addition, I found evidence of a possible effect of psychosocial variables on placebo response. In Study 3, I further tested the nature and correlates of placebo response in a sample of 50 women with sexual arousal and desire problems. These data were drawn from a 12-week double-blind randomized controlled trial in which measurement of symptom severity took place at baseline, 4 weeks, 8 weeks, and 12 weeks, allowing for longitudinal analysis. Change in sexual function during placebo treatment peaked at 4 weeks and remained relatively stable through post-treatment. Furthermore, change in sexual function was clinically meaningful in approximately one-third of the sample. Symptom improvement appeared to be in part a function of increased frequency of satisfying sexual encounters during treatment, although there remained additional variability in outcomes that could not be explained by the available data. The findings are discussed with reference to enhancing both clinical trial design and psychological therapies in the treatment of sexual dysfunction in women. / text