We examined whether nostalgia increases intrinsic motivation in situations of low (vs. high) interactional justice, with downstream implications for work effort. In Study 1, we tested employees of various organizations using experience sampling methodology (ESM). High (vs. low) momentary nostalgia predicted stronger momentary intrinsic motivation, particularly when chronic interactional justice was low (vs. high). In Study 2, another ESM study among employees, we induced nostalgia. Induced nostalgia (vs. control) strengthened momentary work effort, via momentary intrinsic motivation, when chronic interactional justice was low (vs. high). This effect emerged for organizational and personal nostalgia. In Study 3, an experiment, we induced nostalgia and interactional justice. Induced nostalgia (vs. control) increased intrinsic motivation among participants experiencing low (vs. high) interactional justice. This effect of nostalgia was mediated by past-self directedness. In the face of low interactional justice, nostalgia makes employees experience their work as pleasant and motivating, leading them to exert more work effort.