Marcello Bacciarelli was a Polish-Italian painter of the late-baroque and Neoclassic periods.
He was born in Rome, and studied there under Marco Benefial. In 1750, with the recommendation of the architect Gaetano Chiaveri, Marcello was recruited to Dresden in Saxony, where he was employed by Elected King Augustus III of Poland. After the death of King Augustus, Marcello went to Vienna, and thence to Warsaw. In Dresden, he met Bernardo Bellotto and worked with this Italian painter throughout his life. He was recruited by King Stanisław II Augustus in 1768 to become the Director of the newly founded Academy of Arts of Warsaw, as well as director of the Royal Buildings and Estates.

In Dresden, he married Federicka Richter, a woman painter known for miniature portraits. In Vienna, Marcello painted portraits of the imperial family. In Warsaw, he painted a set of portraits depicting nearly all Polish kings, from Bolesław I the Brave to the last king of the Polish–Lithuanian Commonwealth, Stanisław II Augustus who was also Bacciarelli's patron and admirer. He also made a portrait of Izabela Lubomirska in her wedding gown, that she commissioned years later after her marriage. Bacciarelli was also keen in painting culturally significant scenes from the history of Poland. Following the partitions of Poland and after Napoleon's rise to power he moved to the Duchy of Warsaw, a client state of the First French Empire and died in 1818.