Pappus may refer to:
- Pappus (flower structure), a type of flower structure
- Pappus of Alexandria, Greek mathematician
- Pappus's hexagon theorem, often just called 'Pappus's theorem', a theorem named for Pappus of Alexandria
- Pappus's centroid theorem, another theorem named for Pappus of Alexandria
- Johannes Pappus (1549–1610), Lutheran theologian