The Palazzo Colonna (Italian pronunciation: [paˈlattso koˈlonna, - koˈlɔnna]) is a palatial block of buildings in central Rome, Italy, at the base of the Quirinal Hill, and adjacent to the church of Santi Apostoli.

In the 18th century, the long low facade designed by Nicola Michetti, with later additions by Paolo Posi with taller corner blocks (facing Piazza SS.

It includes works by Lorenzo Monaco, Domenico Ghirlandaio, Palma the Elder, Salviati, Bronzino, Tintoretto, Pietro da Cortona, Annibale Carracci (painting of The Beaneater), Guercino, Francesco Albani, Muziano and Guido Reni.

Ceiling frescoes by Filippo Gherardi, Giovanni Coli, Sebastiano Ricci, and Giuseppe Bartolomeo Chiari celebrate the role of Marcantonio II Colonna in the battle of Lepanto (1571).

The older wing of the complex, now known as Princess Isabelle's apartments, but once housing Martin V's library and palace, contains frescoes by Pinturicchio, Antonio Tempesta, Crescenzio Onofri, Giacinto Gimignani, and Carlo Cesi.