Guglielmo Pallotta (November 13, 1727 – September 21, 1795) was an Italian Roman Catholic Cardinal.
Born in Macerata, Marche, he studied hydraulics and law in Rome and then was ordained priest. Later he became auditor of Cardinal Carlo Rezzonico and served in the Fabric of Saint Peter. In 1773 he was named Treasurer general of the Apostolic Camera.
Pallotta was created cardinal priest in the consistory of June 23, 1777 by Pope Pius VI with the title of Sant'Eusebio. On September 23, 1782 he was opted for the title of Santa Maria degli Angeli e dei Martiri and was subsequently named Prefect of the S.C. of Waters, Fountains and Canals. On July 1, 1785 he was made prefect of the S.C. of the Council of Trent until his death. Pallotta was also Camerlengo of the Sacred College of Cardinals from January 29, 1787 to1788.
He died in 1795 in Rome.
- del Re, Nicola (1964). "I cardinali prefetti della sacra congregazione del concilio dalle origini ad oggi (1564-1964).". Apollinaris. XXXVII: pp. 130–131.