Objective: To evaluate the effect of behavioral techniques and physical exercise on psychosocial functioning and health-related quality of life (HRQoL) outcomes in breast cancer patients and survivors. Methods: A meta-analysis was carried out to quantify the effects of behavioral and exercise interventions on fatigue, depression, anxiety, body-image, stress and HRQoL. Summary effect sizes and standard errors were calculated. The presence of publication bias was explored and sensitivity analyses were performed to identify possible sources of heterogeneity. Results: In total, 56 studies were included. Statistically significant results were found for the effect of behavioral techniques on fatigue (ES -0.158; 95% CI -0.233 to -0.082, p<0.001), depression (ES -0.336; 95% CI -0.482 to -0.190, p<0.001), anxiety (ES -0.346; 95% CI -0.538 to -0.154, p<0.001) and stress (ES -0.159; 95% CI -0.310 to -0.009, p=0.038). For the effect of physical exercise interventions, statistically significant results were found on fatigue (ES -0.315; 95% CI -0.532 to -0.098, p=0.004), depression (ES -0.262; 95% CI -0.476 to -0.049, p=0.016), body-image (ES 0.280; 95% CI 0.077 to 0.482, p=0.007) and HRQoL (ES 0.298; 95% CI 0.117 to 0.479, p=0.001). Conclusions: The results indicate that behavioral techniques and physical exercise improve psychosocial functioning and HRQoL in breast cancer patients and survivors. Future research is needed on the effect of physical exercise on stress and the effect of the combined intervention in breast cancer patients.