Individuals with an autism spectrum disorder (ASD) are thought to encounter planning difficulties, but experimental research regarding the mastery of planning in ASD is inconsistent. By means of a meta-analysis of 50 planning studies with a combined sample size of 1755 individuals with and 1642 without ASD, we aim to determine whether planning difficulties do exist and which factors contribute to this. Planning problems were evident in individuals with ASD (Hedges'g = 0.52), even when taking publication bias into account (Hedges'g = 0.37). Neither age, nor task-type, nor IQ reduced the observed heterogeneity, suggesting that these were not crucial moderators within the current meta-analysis. However, while we showed that ASD individuals encounter planning difficulties, the bias towards publishing positive findings restricts strong conclusions regarding the role of potential moderators.