Willingness to communicate (WTC) has been considered an important part of the language learning and communication process, playing a pivotal role in the development of language learners’ communicative competence. Many studies have been conducted on the relationship between WTC and related variables in learning English as a foreign language. However, there is a lack of a comprehensive meta-analysis concerning the effect sizes of these studies. Thus, the present meta-analysis investigated the overall average correlation between L2 WTC and three key variables influencing foreign/second language learners’ WTC, specifically perceived communicative competence, language anxiety, and motivation. The results of the meta-analysis indicated that all three variables were moderately correlated with L2 WTC, with perceived communicative competence having the largest effect. Finally, tests of the heterogeneity of the effect sizes indicated the possibility of the presence of the moderators which might play an influential role in the relationship of WTC with anxiety, perceived communicative competence, and motivation.