A scheduling request triggering method, apparatus, and system are disclosed. The method includes: obtaining, by a terminal device, an uplink semi-persistent scheduling resource allocated by a base station, where the uplink semi-persistent scheduling resource is used to transmit to-be-transmitted data on a logical channel of the terminal device; receiving, by the terminal device, scheduling request masking set by the base station for a first logical channel; and after determining that a triggering condition is satisfied, triggering, by the terminal device, a scheduling request via the first logical channel. In this way, when a status of data of the terminal device changes, an appropriate scheduling resource can be obtained, so as to ensure timely data transmission.