Charles Thomas Caskey (September 12, 1938 – January 13, 2022), also known as C. Thomas Caskey, was an American internist who has been a medical Geneticist and biomedical researcher and entrepreneur. He was a Professor of Molecular and Human Genetics at Baylor College of Medicine, and served as editor of the Annual Review of Medicine from 2001 to 2019. He was a member of the editorial boards of the Proceedings of the National Academy of Sciences, Science, the Encyclopedia of Molecular Medicine and numerous other medical and scientific journals.

Caskey's research over a period of more than 50 years has focused on the genetic basis of human diseases and their molecular diagnosis. He discovered the molecular basis of disease "anticipation" as an expansion of short tandem repeat DNA sequences causative of FragileX, Myotonic Dystrophy, Ataxia, and now over 40 additional diseases (Giovanni Herenzini Foundation Prize). One of his more widely used discoveries was that of a simple PCR test for DNA evidence at crime scenes that is now standard practice among police services in the western world. (Courage in DNA Award, DOJ). It was first validated to clarify Gulf War casualties.