Response variability, a fundamental characteristic of behavior, may be in some cases an induced effect of reinforcement schedules. Research on schedule-induced response variability has shown that continuous reinforcement results in less variability than intermittent reinforcement schedules. Studies on the effects of intermittency of reinforcement, periodicity of reinforcement, and type of schedule have resulted in mixed findings. Contingencies have also been arranged to directly influence operant response variability. These include lag reinforcement schedules, differential reinforcement of novel behavior, differential reinforcement of less frequent behavior, and percentile reinforcement schedules. These procedures are discussed in terms of practicality and implications for use in applied settings. Contingencies and treatment packages that indirectly influence response variability are addressed in terms of response allocation, response generalization, and response covariation. Studies on the effects of a variety of other variables on response variability are also reported, such as levels of food deprivation and drugs. Finally, directions for applied research in response variability are suggested.