This Article develops a framework for effective leniency policy design in jurisdictions that have limited or no mileage enforcing antitrust laws. Through an extensive review of legal and economic studies of leniency and comparative analysis, the Article identifies hurdles common to young systems that may be tackled with analogous solutions. Some issues simply require a methodological enforcement strategy and time. Others, however, call for a readjustment of either the leniency programs or the antitrust systems they help to enforce. While the latter approach is preferable, it is more difficult to implement. This Article focuses on leniency and recommends three general strategies: rethinking the magnitude of the reward where penalties for collusion are modest, reducing discretion to enhance transparency and predictability in the pre-enforcement experience phase, and ensuring a balance between the adequate protection of confidentiality and the need to foster international cooperation efforts to dismantle cartels. These proposals aim to contribute to enhancing the efficiency of new systems and to fostering a “glocalized” deterrent effect that is paramount to combatting the biggest and most harmful collusive practices.