Girolamo Sartonio, also known as Hieronimo Sartorio and Geronimo Sartorio (died April 1707 in Venice), was an innovative Italian architect and engineer who worked mainly the German cities of Hanover, Hamburg, Leipzig and Erfurt.

He was a noted expert in the installation of stage equipment and theatrical machinery and also worked as a builder or consulting architect on the construction of various opera houses, such as the Oper am Gänsemarkt in Hamburg.

During his time he led significant construction projects that beautified the city, including the expansion of the Herrenhausen Gardens and Leineschloss Palace, where he installed a theater and worked on external decorations, the Kapuzinerflügel wing and the court chapel.

He also designed the bridge from the Leineschloss across the Leine River and the Neustädter Kirche, built 1667 to 1670 as an early aisleless church.

During his time in Hanover he wrote a report for the construction of a library in Wolfenbüttel, on a request of Gottfried Wilhelm Leibniz, then a librarian there.