The effectiveness of expressed gratitude interventions in enhancing psychological wellbeing has been explored in a number of studies. The present meta-analysis synthesized results from 25 randomized controlled trials, including a total of 6,745 participants, to examine the effect of expressed gratitude interventions on positive indicators of psychological wellbeing, including life satisfaction, positive affect, and happiness. The results showed that expressed gratitude interventions had a significant effect on psychological wellbeing relative to neutral comparison groups, Hedges’ g = 0.22, 95% CI [0.11, 0.33], p < .001. The significant effects applied to each of the three elements of positive wellbeing. Intervention length and duration from baseline to final assessment did not significantly moderate effect sizes across studies. The present findings indicate that expressed gratitude interventions have value in improving psychological wellbeing.