Persistent emotional memories and intrusive mental images can be weakened by executing a demanding dual-task during recollection of those images and memories. According to working memory (WM) theories, such dual-task interventions are effective because they limit the amount of cognitive resources available for the processing of emotional memories. However, there is still ongoing debate about the extent to which and under what conditions dual-task interventions are effective to interfere with emotional memories. In the current meta-analysis, we assessed k = 44 laboratory experiments investigating the effects of dual-task interventions on negative and positive memories. The effect was measured with the raw mean reduction in vividness and emotionality self-report ratings of emotional memories before compared to after the intervention on 100-point rating scales. Results showed that the dual-task interventions made both negative and positive memories less vivid (mean reduction negative images = 10.83, 95% CI = [8.15, 13.52]; mean reduction positive images = 12.48, 95% CI = [6.73, 15.39]) and less emotional (mean reduction negative images = 11.34, 95% CI = [7.38, 15.30]; mean reduction positive images = 5.35, 95% CI = [2.15, 8.54]). Several moderators were tested and are discussed in the light of WM theories.