World Baseball Classic qualification is the process that determines which nations will compete at the World Baseball Classic. Qualification takes place the year prior to the tournament, which itself is played every four years.
Currently, the World Baseball Classic's main tournament includes 20 nations, an expansion from the 16-team fields of the first four WBCs held between 2006 and 2017. For the fifth edition of the WBC, to be held in 2023, the 16 participating nations from 2017 all received automatic berths; the remaining four slots were filled by the winners and runners-up of two six-team qualifying tournaments. Therefore, twenty-eight nations enter the tournament at any point. To date, thirty nations have entered either qualifying or the main tournament, with Argentina becoming the 30th different nation to participate in a WBC event when it debuted in the qualifying round for 2023.
Unlike other international tournaments such as the Rugby World Cup, FIFA World Cup, and FIBA Basketball World Cup, the qualifying tournaments are not arranged on a regional or geographic basis.