This study aims to illustrate the effects of gamified flipped classrooms (GFC) on students' behavioural, cognitive and affective outcomes in formal educational settings. Based on the PRISMA reporting guidelines, we systematically identified and screened articles from five databases: Web of Science, Scopus, Wiley Online Library, ProQuest and ERIC. Finally, 21 effect sizes from 13 articles on behavioural outcomes, 38 effect sizes from 19 articles on cognitive outcomes and 16 effect sizes from 11 articles on affective outcomes were included in this study. Then, we use CMA 3.0 software to conduct the meta-analysis for the selected articles. The calculated effect sizes indicate that GFC had a more positive effect on students' behavioural, cognitive and affective outcomes compared to traditional lectures. Using a random effects model, we calculated two statistically significant medium overall effect sizes--Cohen's d = 0.409 for the behavioural outcome, Cohen's d = 0.400 for the affective outcome--and a statistically significant small overall effect size--Cohen's d = 0.285 for the cognitive outcome. In addition, through the publication bias test, we did not find that this study was threatened by publication bias. Moderator variable analysis demonstrated that year of publication, region, educational level, subject, treatment (intervention) duration, and learning environment were significant variables influencing the effects of GFC on behavioural, cognitive and affective outcomes. Overall, the results of this study suggest that GFC significantly improved students' behavioural, cognitive and affective outcomes.