Vaccines are one of the few medical procedures that are usually more for the common good than the individual good of the patient. As we can more often require people to serve the common good than their own particular good, vaccines are the most often mandated medical procedure. These mandates can be of different levels, such as for staff or individuals in high-risk places, for travels to/from a country, or for almost the whole population like public school vaccine mandates. This chapter explores the ethics of vaccine mandates, indicating both the ethics of existing mandates and principles for possible future mandates. To force someone to act for the common good, there must be a great advantage to the common good compared to the little danger or disadvantage to them: it must be substantially more than what might be taken from the individual. Vaccines have a variety of factors that affect the common or individual good, including the mode and probability of disease transmission, disease danger, disease change cycle, vaccine efficacy, dangers of vaccine side-effects, the mandate’s breadth, etc. This chapter argues in favor of most existing mandates and many proposed ones, but is not in support of every proposed mandate.