The following is a list of squads for each nation competing at 2006 World Baseball Classic. The tournament began on March 3 and the final took place on March 20, 2006.
The teams listed on the country's roster is the team the player was with while the tournament took place.
^Quantrill announced his retirement during the 2006 WBC, effective at the end of the tournament.
^Guerrero will skip the first round of the World Baseball Classic, due to the death of three of his cousins in an auto accident in the Dominican Republic. "Notes: Vladdy in Dominicans' thoughts". Archived from the original on 2007-05-26. Retrieved 2006-03-05.