This is a list of Portuguese winter football transfers for the 2010–11 season. The winter transfer window opened on 1 January 2011 and closed on 31 January 2011. Players could be bought before the transfer window opened, but were not permitted to join their new clubs until 1 January. Additionally, players without a club could join at any time and clubs were able to sign a goalkeeper on an emergency loan if they had no registered goalkeeper available. Only moves involving Primeira Liga clubs are listed; included are clubs that completed transfers after the closing of the summer 2010 transfer window due to other domestic leagues having a later closure date to their transfer window.