Alcoholism is a serious health problem that affects the lives of millions of people worldwide. People that first experiment with alcohol as adolescents are at a greater risk to become alcoholics. The adolescent brain may be particularly vulnerable to drug-induced neuroadaptations. Behavioral sensitization is a method that uses repeated drug exposure to induce neurobiological changes that are thought to model the changes taking place during addiction. Sensitization to ethanol has not been studied in adolescents and is an important tool to aid in the understanding of ethanol-induced neuroadaptations that occur during development. The research described in this dissertation entailed the study of the dose response and time course of ethanol sensitization in adolescent and adult mice. The results indicate that adolescent mice are less sensitive to ethanol sensitization than adult mice. The neurobiological mechanisms mediating ethanol sensitization have not been fully characterized. One type of glutamate receptor, the metabotropic glutamate receptor subtype 5 (mGluR5), is involved in drug reinforcement, relapse, and reward processes, although it has not been studied in adolescent ethanol sensitization. Results of the research described in this dissertation showed that mGluR5 is not involved in adolescent ethanol sensitization, while it is critical in adult ethanol sensitization. This indicates that mGluR5 might underlie the differential response to ethanol sensitization in adolescent and adult mice. Finally, this research was designed to determine whether the differential response to ethanol sensitization makes the adolescent mice more susceptible to subsequent ethanol intake. The results show that, following ethanol sensitization, the adolescent mice do not show increased ethanol intake, while the adult mice demonstrate a significant increase in ethanol intake and preference. Overall, this dissertation shows for the first time that adolescent mice are less sensitive to ethanol sensitization than adult mice. This difference in sensitization, however, does not appear to underlie the adolescent vulnerability to alcoholism that has been observed in humans.