Activity scheduling is a behavioral treatment of depression in which patients learn to monitor their mood and daily activities, and how to increase the number of pleasant activities and to increase positive interactions with their environment. We conducted a meta-analysis of randomized effect studies of activity scheduling. Sixteen studies with 780 subjects were included. The pooled effect size indicating the difference between intervention and control conditions at post-test was 0.87 (95% CI: 0.60 - 1.15). This is a large effect. Heterogeneity was low in all analyses. The comparisons with other psychological treatments at post-test resulted in a non-significant pooled effect size of 0.13 in favor of activity scheduling. In ten studies activity scheduling was compared to cognitive therapy, and the pooled effect size indicating the difference between these two types of treatment was 0.02. The changes from post-test to follow-up for activity scheduling were non-significant, indicating that the benefits of the treatments were retained at follow-up. The differences between activity scheduling and cognitive therapy at follow-up were also non-significant. Activity scheduling is an attractive treatment for depression, not only because it is relatively uncomplicated, time-efficient and does not require complex skills from patients or therapist, but also because this meta-analysis found clear indications that it is effective.