As of the 2018 FIFA World Cup, 79 national teams have competed in the final tournaments. This will become 80 after Qatar makes its debut in 2022. Mexico has qualified without winning the World Cup tournaments more than any other country (16 times). They’ve even been the host country twice in 1970 and 1986.
The country with the smallest population to ever compete in the FIFA World Cup is Iceland (population: 334,000)