Quoc: The Premier League is an English professional league for men's association football clubs. At the top of the English football league system, it is the country's primary football competition. Contested by 20 clubs, it operates on a system of promotion and relegation with the English Football League (EFL; known as "The Football League" before 2016 -- 17). Welsh clubs that compete in the English football league system can also qualify.

How many teams in the english premier league?
HW Chung: OK, some thoughts:
The relevant sentence in the passage is: Contested by 20 clubs, it operates on a system of promotion and relegation with the English Football League (EFL; known as "The Football League" before 2016 -- 17). The answer is 20.