Four schools

The four schools usually refer to

• the four main schools of Tibetan Buddhism:

1. Nyingma
2. Sakya
3. Kagyü
4. Gelug

However, the term can also sometimes refer to

• the four schools of Buddhist philosophy:

1. Vaibhashika
2. Sautrantika
3. Chittamatra
4. Madhyamika

For more details, see four tenet systems.