Single-longitudinal-mode Q-switched laser sources are widely used in various fields such as precision measurements. The fiber laser is one of new-generation solid-state laser with many excellent properties. Recently lots of techniques for single-longitudinal-mode Q-switched fiber lasers were rapidly developed. The operation principles, current available techniques and possible development trends of fiber lasers for single-longitudinal-mode Q-switched pulses, including both introducing the Q-switch into the single-longitudinal-mode fiber laser and injecting a single-longitudinal-mode laser seed into the Q-switched fiber laser, are comprehensively overviewed.