The aims of the present analysis were to investigate the short- and long-term efficacies and treatment moderators of psychological interventions for fibromyalgia. A literature search using PubMed, PsychINFO, the Cochrane Library, and manual searches identified 23 eligible studies including 30 psychological treatment conditions and 1396 patients. Meta-analytic integration resulted in a significant but small effect size for short-term pain reduction (Hedges's g=0.37, 95% confidence interval (CI): 0.27-0.48) and a small-to-medium effect size for long-term pain reduction over an average follow-up phase of 7.4 months (Hedges's g=0.47, 95% CI: 0.3-0.65) for any psychological intervention. Psychological treatments also proved effective in reducing sleep problems (Hedges's g=0.46, 95% CI: 0.28-0.64), depression (Hedges's g=0.33, 95% CI: 0.20-0.45), functional status (Hedges's g=0.42, 95% CI: 0.25-0.58), and catastrophizing (Hedges's g=0.33, 95% CI: 0.17-0.49). These effects remained stable at follow-up. Moderator analyses revealed cognitive-behavioral treatment to be significantly better than other psychological treatments in short-term pain reduction (Hedges's g=0.60, 95% CI: 0.46-0.76). Higher treatment dose was associated with better outcome. Publication-bias analyses demonstrated that the effect sizes were robust. The results suggest that the effects of psychological treatments for fibromyalgia are relatively small but robust and comparable to those reported for other pain and drug treatments used for this disorder. Cognitive-behavioral therapy was associated with the greatest effect sizes.