Wat Mahathat (Thai: วัดมหาธาตุ) is the common short name of several important buddhist temples in Thailand. The name may refer to:
- Wat Mahathat Yuwarajarangsarit (Rajaworamahavihara), Bangkok
- The ruins of Wat Phra Si Rattana Mahathat (Woravihara), Sukhothai, at Sukhothai Historical Park, a UNESCO World Heritage Site
- Wat Phra Si Rattana Mahathat (Woramahavihara), Phitsanulok
- Wat Phra Mahathat (Woramahavihara), Nakhon Si Thammarat