Guido Altarelli (12 July 1941[1] – 30 September 2015[2]) was an Italian theoretical physicist.

In 1970-92 he held a faculty position at the Sapienza University of Rome (full professor of theoretical physics since 1980).

In 1992 he moved to the newly established University of Roma Tre.

In 2011 Altarelli gave a talk The Mystery of Neutrino Mixing at the international symposium on subnuclear physics held in Vatican City.

[6] His best known contribution, obtained with Giorgio Parisi in 1977, is the derivation of the QCD evolution equations for parton densities, known as the Altarelli- Parisi or DGLAP equations.