Quarto Cagnino is a district ("quartiere") of Milan, Italy, part of the Zone 7 administrative division of the city. It borders onto the districts of Trenno (north), San Siro (east), Baggio (south), and Quinto Romano (west). Before being annexed to Milan, in 1869, it has been an autonomous comune and, briefly, a part of Trenno (from 1861 to 1869).

Quarto Cagnino is a formerly rural, now urban district, with the last period of quick urban development having occurred in the late 1960s in so called "GESCAL" projects. The "GESCAL" acronym stands for "Gestione Case per i Lavoratori", i.e., "Housing for Workers"; these projects were meant to realized vast low-income apartment blocks in rationally organized, "satellite" city neighbourhoods. Example of GESCAL apartment flats are found along Via Carlo Marx, close to the San Carlo hospital. While low-income, huge apartment buildings dominate the landscape of Quarto, these contrast with some remaining ancient cascine, testifying the rural past of the district. These are mostly found along Via Fratelli Zoia, which used to be the main street of old rural Quarto Cagnino.