Dario Marianelli (born June 21, 1963) is an Italian composer of piano, orchestral, and film music.

Marianelli was born in Pisa, Italy. He has composed the soundtracks for The Brothers Grimm (2005), Pride & Prejudice (2005), Atonement (2007), and Anna Karenina (2012), the last three for which he received Oscar nominations for Best Achievement in Music Written for Motion Pictures, Original Score. In 2008, Marianelli won both an Oscar and Golden Globe for the score of Atonement.