Richard Streit Hamilton (born 1943) is Davies Professor of mathematics at Columbia University.

He received his B.A in 1963 from Yale University and Ph.D. in 1966 from Princeton University. Robert Gunning supervised his thesis. Hamilton has taught at UC Irvine, UC San Diego, Cornell University, and Columbia University.

Hamilton's mathematical contributions are primarily in the field of differential geometry and more specifically geometric analysis. He is best known for having discovered the Ricci flow and suggesting the research program that ultimately led to the proof, by Grigori Perelman, of the Thurston geometrization conjecture and the solution of the Poincaré conjecture. In August 2006, Perelman was awarded, but declined, the Fields Medal for his proof.

Hamilton was awarded the Oswald Veblen Prize in Geometry in 1996 and the Clay Research Award in 2003. He was elected to the National Academy of Sciences in 1999 and the American Academy of Arts and Sciences in 2003. He also received the AMS Leroy P. Steele Prize for a Seminal Contribution to Research in 2009.

On 18 March 2010, it was announced that Perelman had met the criteria to receive the first Clay Millennium Prize for resolution of the Poincaré conjecture. On July 1, 2010, he turned down the prize, saying that he believes his contribution in proving the Poincaré conjecture was no greater than that of Hamilton, who first suggested a program for the solution. In June 2011, it was announced that the Million - dollar Shaw Foundation Prize would be split equally between Hamilton and Demetrios Christodoulou.