World Chess Championship 1966
| Defending champion | Challenger | |||||
| Tigran Petrosian | Boris Spassky | |||||
| 
 | ||||||
| Born 17 June 1929 36 years old | Born 30 January 1937 29 years old | |||||
| Winner of the 1963 World Chess Championship | Winner of the 1965 Candidates Tournament | |||||
A World Chess Championship was played between Tigran Petrosian and Boris Spassky in Moscow from April 9 to June 9, 1966. Petrosian won.