Sporus of Nicaea (Greek: Σπόρος; c. 240 – c. 300) was a Greek mathematician and astronomer, probably from Nicaea, ancient district Bithynia (modern-day Iznik) in province Bursa, in modern-day Turkey.

Much of his work focused on squaring the circle and reproducing cubes, both in his own attempts at these problems or in criticizing the work of other contemporary mathematicians. Sporus criticized Archimedes for not producing a more accurate approximation of π.

• O'Connor, John J.; Robertson, Edmund F., "Sporus of Nicaea", MacTutor History of Mathematics Archive, University of St Andrews