Alessandro Casolani (1552–1606) was an Italian painter of the late-Renaissance period, active mainly in Siena.
He was also called Alessandro della Torre. He was born at Siena, and was the pupil of Ventura Salimbeni and of Cristoforo Roncalli. His works are principally in the churches of Siena, but are also found in Naples and Genoa. He also etched one plate, a Madonna, and the frescoes at Certosa di Pavia with Pietro Sorri.
His son, Ilario Casolani was also a painter.
Among the pupils of Casolani are Bernardino Capitelli, Sebastiano Folli, and Giovanni Biliverti.