Pietro Paolo Floriani (26 April 1585 – 27 May 1638) was an Italian engineer and architect who designed military and theatrical buildings.

[2] In autumn 1612 Floriani settled in Madrid, Spain, where King Philip III commissioned him for a number of projects including to explore the fortifications of Algiers to plan a conquest of the city.

In 1617 Floriani was sent to work for the Governor of Milan Pedro Álvarez de Toledo, who had begun an extensive defensive engineering program.

Floriani spent about a year in Milan, and although the King of Spain invited him to return to the Algiers project, he declined as he had been commissioned by Archduke Leopold V to fortify the town of Brisach in Hungary.

Floriani had written his will in 1632 in which he asked to be buried with his brother Felice who had died in 1630 at the church of Santa Croce in Macerata.