The effectiveness of computer-assisted instruction in language learning has been the topic of a long-standing debate. Prompted by this debate, we attempted to provide an updated meta-analysis on the learning effect of computer-assisted English language instruction on a broad range of study features. This meta-analysis of the experimental literature compares computer-assisted English language learning with traditional face-to-face treatments, including 140 computer-assisted learning versus classroom instruction studies, which yield 158 achievement effects. After examining the methodological quality, the overall weighted average effect size for achievement was +0.50, and it was heterogeneous. The results indicated that computer-assisted instruction had an overall medium effect on English language development. Moreover, the mixed effects model for moderator analyses indicated that Web-based instruction yielded a larger mean effect (+0.54) than traditional computer-assisted instruction (+0.47). Further analyses led to the identification of four important moderators of English language learning: type of interaction, communication mode, language learning context, and treatment duration. Insights into the evolution, not only in the technological but also in the sociological context and educational theories, and the future prospects of computer-assisted instruction are discussed.