Empirical studies have found that policies aimed at reducing youth access t
o tobacco have been successful at increasing retail compliance, but their e
ffects on actual tobacco use are mixed. This article presents a model of yo
uth access policies that helps explain the apparently conflicting results i
n the extant literature, provides a framework for future empirical studies,
and suggests implications for public policy. Our model highlights the inte
raction of components in a well-designed policy, including sufficient compl
iance checks, penalties, and community involvement. It also illustrates why
it will be difficult to eliminate all of youth supply. Nonretail sources,
such as borrowing or stealing from parents and siblings and purchasing from
older peers through black markets, are an important component of youth sup
ply and become more important as retail access is reduced. The analysis is
limited to policies that affect the retail supply of cigarettes but suggest
s the need for other policies that affect the demand for cigarettes, such a
s taxes and cessation policies, in order to further reduce youth smoking ra
tes.