David A. Tirrell (born 1953) is an American chemist and the Ross McCollum-William H. Corcoran Professor and Professor of Chemistry and Chemical Engineering at the California Institute of Technology (Caltech). A pioneer in the areas of polymer synthesis and protein biosynthesis, his research has a wide range of applications, including coatings, adhesion, lubrication, bioengineering and biomedical intervention. From 2012 to 2018, Tirrell was the Director of the Beckman Institute at Caltech. As of 2017, he serves as Caltech's Provost. He is one of very few American scientists to have been elected to all three branches of the United States National Academies: the National Academy of Sciences (2006), the National Academy of Engineering (2008), and the Institute of Medicine (2011). He was electe