Indirect food additives are the additives that are not intended to be added directly to foods but are added to food contact articles namely, food packaging. In this chapter, the main indirect additives are reviewed, as well as, the legal aspects and regulatory control applied to these kinds of substances in the USA and the European Union. The migration of some of these compounds to foods is undesired and, in some cases, may represent a threat to human health. This chapter also highlights some specific groups of indirect additives including monomers, plasticizers, antioxidants and antimicrobials, catalysts, initiators, curing and cross-linking agents, stabilizers, and solvents. Future trends in the use of indirect additives are also discussed in this chapter. Innovative technologies in the food packaging industry are emerging every day, so the regulations and the regulatory agencies must be updated.