List of Spanish football transfers winter 2017–18

This is a list of Spanish football transfers for the winter sale in 2017–18 season of La Liga and Segunda División. Only moves from La Liga and Segunda División are listed.

The winter transfer window opened on 1 January 2018, although a few transfers took place prior to that date. The window closed at midnight on 31 January 2018. Players without a club can join one at any time, either during or in between transfer windows. Clubs below La Liga level can also sign players on loan at any time. If need be, clubs can sign a goalkeeper on an emergency loan, if all others are unavailable.