In the past 15 years, both human and animal studies have advanced our understanding of the effects of adolescent alcohol exposure on behavioral and neural development, particularly in the areas of the ontogeny of initial sensitivity and tolerance to alcohol, the consequences of adolescent alcohol exposure on subsequent drinking patterns, as well as cognitive and neural function. Despite these advances, there are still substantial gaps in our understanding of whether heavy adolescent drinking interferes with normal brain development at the cellular and molecular level, and if so, how these changes may translate into patterns of brain connectivity that result in the emergence of alcohol use disorders. This article discusses our current knowledge of the cellular and molecular brain changes that stem from heavy alcohol exposure, including binge patterns, during adolescence. Progress has been made in linking the behavioral effects of adolescent drinking to underlying cellular and molecular mechanisms. However, it is suggested that future research on the etiology and consequences of adolescent drinking use an integrative approach to this problem by combining multiple levels, including genetic, cellular and molecular, systems (neuroimaging), and behavioral, with an emphasis on integrating the different levels of analysis.