This application provides a sidelink communication method, a terminal device, and a network device. In the sidelink communication method, a network device determines downlink control information. The downlink control information carries first indication information. The first indication information is used to indicate slot formats respectively corresponding to the terminal devices in K terminal device pairs. A terminal device pair is two terminal devices performing sidelink communication between themselves. K is a positive integer. The network device sends the downlink control information. In the technical solutions provided in this application, the network device may configure a slot format for the terminal devices in the terminal device pairs.