Purpose: To propose that the diagnostic category of "expressive language disorder" as distinct from a disorder of both expressive and receptive language might not be accurate. Method: Evidence that casts doubt on a pure form of this disorder is reviewed from several sources, including the literature on genetic findings, theories of language impairments, and the outcomes of late talkers with expressive language delays. Areas of language that are problematic in production but not readily amenable to comprehension testing are also discussed. Conclusions: The notion of expressive language disorder has been formalized in classification systems and is implicit if not explicit in the organization of many standardized tests. However, a close inspection of the evidence suggests that deficits in language expression are typically accompanied by limitations in language knowledge or difficulties processing language input. For this reason, the diagnostic category of expressive language disorder should be used with considerable caution. This view has implications for both research and clinical practice.