Joe Robert Greenhill (July 14, 1914 – February 11, 2011) was an American attorney. He served on the Texas Supreme Court for 25 years, 10 of those as Chief Justice.
Born in Houston, Texas, Greenhill got his law degree from the University of Texas in 1939 where he was a member of the Texas Cowboys. During World War II, he served as junior officer in the United States Navy, first in intelligence and then as executive officer of a mine sweeper in the Pacific Theater. He became Assistant Attorney General of the State of Texas in 1948, co-founded Graves, Dougherty & Greenhill in 1950 and was appointed to the Texas Supreme Court in 1957, where he served until 1982. He received an honorary Doctor of Law degree from Southern Methodist University in 1977.
Greenhill was of counsel at Baker Botts.