Testudo may refer to:
- Testudo (genus), a genus of tortoises
- The Latin variant of the Greek chelys harp made from a tortoise shell
- The testudo formation, a Roman military tactic
- Battering ram, an armored siege engine of antiquity, with metal plating on the top to protect from missiles fired from above
- The name of the official mascot of the University of Maryland, College Park, a diamondback terrapin
- Testudo, an obsolete constellation now in the constellation of Pisces
- Testudo, an alternative name of the constellation Lyra