Retired Marine Corps Col. William P. Nesbit, 56, a combat veteran of World War I, the Korean conflict and the Vietnam war, died Saturday at Fairfax County Hospital after a heart attack.

He was stricken while performing in a musical show at the Springfield Golf and Country Club, were he was an active member. Col. Nesbit had been teaching mathematics at Mount Vernon High School for the past four years.

Born in Rome, Pa., he was a 1942 graduate of Pennsylvania State University. He then entered the Marine Corps and served during World War II as commanding officers of a marine detachment aboard the heavy cruiser U.S.S. Boston, which saw combat in the Pacific.

He was sent to Korea during the conflict there.He was in Vietnam as senior adviser to the commandant of the Vietnamese Marine Corps until 1965.

Col Nesbit's last assignment before retiring from military duty in 1967 was with the Office of the Joint Chiefs of Staff.

He was a member of the Marine Corps Retired Officers Association and the Masons.

He is survived by his wife, Betty, of the home in Springfield; two daughters, Patricia Charbonneau, of Beltsville, and Michelle Marie, of Rochester, N.Y., and two grandchildren.