This paper presents an overview of construct validity and its' definitions and implications in language testing.Construct validity has gained momentum among language testers and teachers for the last decades or so.Unfortunately, not many people fully understand how to conduct a well designed construct validated test.It is hoped that this paper can provide some guidance and support to those who want to embark on construct validity investigations.Topics analyzed in this study included; the concept of validity and construct validity, qualitative and quantitative measures of construct validity; and the review of some studies that applied these measures.