Donato Bilancia (10 July 1951 – 17 December 2020) was an Italian serial killer who murdered seventeen people – nine women and eight men – on the Italian Riviera in the period from October 1997 to May 1998.

Bilancia's inconsistent modus operandi made him difficult to identify and capture. There were no obvious links between the majority of his murders. He chose most of his victims at random, across a vast area of Northern Italy, and became a synonym for fear among the people living along the Italian Riviera. He was given the nicknames Mostro della Liguria ("The Liguria Monster") and L'assassino dei treni ("Killer on the trains").

Initially attributed with only nine homicides by the Italian police, Bilancia later confessed to having killed eight other people. With a sentence to 13 terms of life imprisonment, and no possibility of release, Bilancia has been defined by some newspapers as "the worst serial killer in the history of Italy". Bilancia died on 17 December 2020, in prison, because of COVID-19.