Dionicio Cerón Pizarro (born October 9, 1965 in Toluca) is a former marathon runner from Mexico, whose personal best in the classic distance was 2:08:30.
He represented his native country two times at the Summer Olympics: in 1992 and 1996.
He also won the London Marathon three consecutive times between 1994 and 1996, the only athlete to have ever achieved this feat.
Eluid Kipchoge and António Pinto are the only other athletes to have won it 3 times, however not in consecutive years.