BACKGROUND Overestimation of the amount that other students drink is related to alcohol-related problems. Although beliefs concerning students' friends tend to be stronger predictors of drinking than beliefs regarding students generally, little research has focused on overestimation of friends' drinking-related problems. OBJECTIVES Test hypotheses that students overestimate a close friend's drinking-related problems and that such overestimation would relate to more frequent drinking and related problems. METHOD Participant/Friend pairs (N=55) completed online measures of drinking-related beliefs and behaviors. RESULTS Participants overestimated the alcohol-related problem severity experienced by their friends. Greater overestimation of friends' problems was related to greater participant alcohol-related problems and binge drinking. CONCLUSIONS/IMPORTANCE Cognitive distortions regarding a friend's drinking-related behaviors may be useful therapeutic targets.