Abstract: This chapter describes the principal arguments about intellectual property rights as mechanisms for promoting the public interest, as opposed to particular private interests. Public interest arguments typically feature in balancing accounts of intellectual property rights that evince concern for the distribution of benefits as well as for the production of new works or inventions. Public interest rationales also often feature in justifications both for the rights themselves and for limitations or exceptions to those rights when private control of an intellectual resource would not promote the general welfare. The chapter considers patents, copyright, trademarks, and related rights, including the right of publicity. It concludes by examining various challenges faced by public interest accounts.