Delayed reinforcement, sometimes delivered just after the setting in which the critical behavior had occurred (Early), and sometimes delivered only after several further settings had been encountered (Late), was used to improve a variety of behaviors in seven preschool children, and to control their generalization. Performance of those behaviors was measured in two classroom settings: the Contingent setting, within which performance of the specified behavior determined the later (Early or Late) reinforcement, and the Generalization setting, in which there were no experimental contingencies, immediate or delayed, for the performance of the same behavior. Performances by all children in the Contingent setting were controlled by delayed reinforcement, whether Early or Late. All children showed consistent generalization from the Contingent setting to the Generalization setting during the Late condition, when reinforcement was delivered at the end of the school day. Generalization did not occur during the Early condition, when reinforcement was provided immediately after the Contingent setting (prior to the Generalization setting), unless that condition had been preceded by a Late condition (as it was for S6and S7). The results suggest that the Late timing of delayed reinforcement was an effective and efficient generalization‐promotion technique for performances that did not generalize spontaneousl