Lorenzo Mascheroni (May 13, 1750 - July 14, 1800) was an Italian mathematician, born near Bergamo, Italy.

At first mainly interested in the humanities (poetry and Greek language), he eventually became professor of mathematics at Pavia.

In his Geometria del Compasso (Pavia, 1797), he proved that any geometrical construction which can be done with ruler and compasses, can also be done with compasses alone. However, the priority for this result (now known as the Mohr-Mascheroni theorem) belongs to the Dane Georg Mohr, who published a proof already in 1672.

In his Adnotationes ad calculum integrale Euleri (1790) he published a calculation of what is now known as the Euler-Mascheroni constant.

He died in Paris.