Self-presentation is a form of impression management through which individuals plan, adopt, and execute the process of conveying an image of self to others in order to gain desired responses from them. Protective self-presentation is a behavioral style motivated by the desire to avoid incurring social disapproval or significant losses in social approval. Students who prefer the more protective style of self-presentation may refrain from or limit alcohol use because they believe it is important to avoid experiencing interpersonal consequences such as embarrassing themselves, garnering social disapproval, or potentially losing social approval due to drinking. In contrast, acquisitive self-presentation is a behavioral style motivated by the desire to actively gain social approval from other people. This may result in the use and abuse of alcohol as a means of fitting in with the crowd that values alcohol consumption. The current study examined the links between self-presentation style, diffidence, alcohol expectancies, and alcohol use. Participants were 548 college students who participated in the 1996 University Life Transitions Residence Hall Survey. The variables used in the study were diffidence, which was a component score that combined introversion, self-esteem, and loneliness scales; positive and negative alcohol expectancies, which were used to operationalize self-presentation styles; and planned frequency and quantity of alcohol use in the next year. Correlational and multiple regression analyses were used to examine whether protective and acquisitive self-presentation expectancies about the effects of alcohol acted as suppressing variables in the relationship between diffidence and alcohol use. The study findings supported the suppression hypothesis, in that there was a negative relationship between diffidence and alcohol use when self-presentation expectancies about the effects of alcohol were controlled statistically. Possible reasons why people with diffidence characteristics drink less alcohol are discussed, and some implications are drawn for campus alcohol prevention programs. 2 tables, 2 figures, 49 references, and appended listing of characteristics of protective and acquisitive alcohol expectancies