There has been a growing emphasis on researching foreign language boredom in second language acquisition in recent years. However, existing research has yet to reach a consensus regarding the effect of foreign language boredom on learners’ learning achievement. To address this gap, the present study employs multilevel meta-analysis to analyze 47 effect sizes from 33 empirical studies involving a total sample size of 27,838 participants. The findings reveal that foreign language boredom illustrates a small negative effect (r = -.24, p < .001) on language achievement. Furthermore, the moderation analysis reveals that the magnitude of the effect size varies crossing educational stages, achievement measurements, domain-specific language skills, foreign language boredom measurements, teaching modes, and learning contexts. This study provides robust evidence to support the detrimental role of foreign language boredom in language acquisition and identified substantive gaps in this research field, offering valuable directions for future research.
