Caffeine is the most widely available and consumed psychoactive substance in the United States. Extant work indicates that across substances, use expectancies play a marked role in the development and maintenance of consumption patterns. Despite a burgeoning line of etiological and intervention-oriented research focused on expectancies (e.g., alcohol), there is a limited literature regarding caffeine use effect expectancies, specifically. To facilitate this work, the Caffeine Expectancy Questionnaire (CaffEQ) was developed and psychometrically validated; however, the length of the CaffEQ (i.e., 47 items) may hinder widespread adoption of this tool. As such, the current study provides an initial psychometric validation of a brief, 20-item version-the Brief-Caffeine Expectancy Questionnaire (B-CaffEQ)-in a multiethnic sample of undergraduate students (N = 975). Results showed that the B-CaffEQ replicated the 7-factor structure of the original CaffEQ using both constrained (confirmatory factor analysis) and less constrained (exploratory structural equation modeling) structural models and evidenced good internal consistency across subscales. The B-CaffEQ also demonstrated concurrent validity with caffeine use frequency indices, replicated and extended convergent validity between caffeine expectancy subscales and related behavioral and psychological constructs, and demonstrated discriminant validity with other related, but notably distinct, stimulant use metrics (e.g., cocaine, Ritalin). Lastly, the B-CaffEQ appears to provide an invariant measure of expectancies across types of caffeine users. These findings indicate that the B-CaffEQ is a reliable assessment of caffeine use effect expectancies, with acceptable-to-good psychometric properties-comparable in length to other substance use expectancies measures-that may be more readily incorporated into research and clinical settings. (PsycINFO Database Record (c) 2018 APA, all rights reserved).