Cognitive diagnostic assessment is known for its capacity to provide detailed feedback to test-takers, which can inform instruction and guide learning. Besides this core strength of the assessment approach, the measurement procedure also works as a construct validation method in itself. Previous studies do not call attention to this aspect of cognitive diagnostic assessment and how the CDA validation can be different from existing construct validation methods. Thus, the purpose of this article is to synthesize cognitive diagnostic assessment research from a standpoint of seeing it as a construct validation procedure with a focus on its strengths as such. In doing so, the article closely examines studies that applied two earlier cognitive diagnostic models to learner data because they established the research foundations of CDA in language testing. Before looking into the details of the procedure of cognitive diagnostic assessment, the paper critically reviews non-CDA studies on construct validation in language testing. It then scrutinizes the methods and objects of construct validation in CDA research to find any significant differences. The paper concludes with several avenues of future research in CDA, which are related to the matter of verifying test constructs.