A method for determining a feedback resource in a sidelink includes a first terminal sending SCI to a second terminal, where the SCI includes indication information. The indication information is used to indicate a first resource or a first resource window to be occupied for sending hybrid automatic repeat request HARQ feedback information by the second terminal, and the first resource window includes a plurality of candidate first resources. The method further includes the first terminal receiving, on the first resource, the HARQ feedback information sent by the second terminal, or monitors, in the first resource window, the HARQ feedback information sent by the second terminal.