Masten Gregory (February 29, 1932, Kansas City, Missouri − November 8, 1985, Porto Ercole, Tuscany, Italy) was a racing driver from the United States. He raced in Formula One between 1957 and 1965, participating in 43 World Championship races, and numerous non-Championship races.
After the end of the 1.5 liter formula in 1965, Gregory retired from single seater racing, but continued in sports cars for several years. Upon the death of his good friend Jo Bonnier at Le Mans in 1972, he retired from racing altogether, and became a merchant of diamonds and glassware. He died of a heart attack at his winter home in 1985.