Gian Francesco Giudice (born 25 January 1961) is an Italian theoretical physicist working at CERN in particle physics and cosmology.

After being employed by the Istituto Nazionale di Fisica Nucleare of Italy, in 1993 he moved to CERN, where is currently the Head of the Theoretical Physics Department.

Academician of the Accademia dei Lincei, the Istituto Veneto di Scienze, Lettere ed Arti, and Accademia Galileiana, he has been awarded the Jacques Solvay Chair in Physics at the Université libre de Bruxelles (2013), Distinguished Visiting Research Chair at Perimeter Institute for Theoretical Physics (2019), Sackler Distinguished Lecturer at Tel Aviv University (2020), Chandrasekhar Lecturer at Tata Institute of Fundamental Research (2022), Erwin-Schrödinger Professor at the University of Vienna (2023).

Together with physicist Riccardo Barbieri, he proposed[1] a widely used criterion to test the degree of naturalness of a supersymmetric theory that achieves electroweak symmetry breaking.

[9] Giudice has played an active role in studying the physics potential of particle accelerators, supporting and advocating several new projects at CERN and in other laboratories worldwide.