Diversity policies and programs, whether adopted by employers, institutions of higher education, or even government agencies, have long garnered both wide praise and forceful objection. Those who support diversity efforts insist that they are necessary to achieve a range of important objectives from remedying the harms of past discrimination to leveraging the epistemic benefits of diverse perspectives, or even enacting basic principles of representative democracy. On the other side, opponents assail these same efforts by pointing to what they assert are their harmful, divisive, and unjust effects. Perhaps the most important area of disagreement between the two sides is when, if ever, diversity efforts are permitted as a matter of law. Investigating both sides of this debate and each of the arguments in turn, this chapter will explore the legal arguments for and against diversity policies and programs, evidencing when they are most likely to be legally permissible and when, conversely, they are most vulnerable to legal attack.