Douglas Fred Tewell (born August 27, 1949) is an American professional golfer who has won numerous tournaments at both the PGA Tour and Champions Tour level, including two senior major championships.

Tewell was born in Baton Rouge, Louisiana and reared in Stillwater, Oklahoma. He got started in the game by working as a caddie for his father. He attended Oklahoma State University in his hometown on a basketball scholarship his freshman year, but later switched to golf. Tewell graduated and turned pro in 1971.

Tewell joined the PGA Tour in 1975; his best year came in 1980 when he won the Sea Pines Heritage and IVB-Golf Classic. He won two more times on the Tour in the mid-1980s. His best finishes in a major were T-9 at the 1983 PGA Championship and T-10 at the 1986 PGA Championship. Tewell was forced off the PGA Tour at the age of 46 at the end of the 1995 season due to an orthopedic problem in his left elbow. He had arthroscopic surgery on the same elbow in 2005, a procedure he describes as "cleaning out scar tissue".