Purpose: The purpose of this article is to review and discuss theories of working memory with special attention to their relevance to language processing. Method: We begin with an overview of the concept of working memory itself and review some of the major theories. Then, we show how theories of working memory can be organized according to their stances on 3 major issues that distinguish them: modularity (on a continuum from domain-general to very modular), attention (on a continuum from automatic to completely attention demanding), and purpose (on a continuum from idiographic, or concerned with individual differences, to nomothetic, or concerned with group norms). We examine recent research that has a bearing on these distinctions. Results: Our review shows important differences between working memory theories that can be described according to positions on the 3 continua just noted. Conclusion: Once properly understood, working memory theories, methods, and data can serve as quite useful tools for language research.