Studies continue to show that the majority of men who have sex with men (MSM) in the US remain unvaccinated against the hepatitis A virus (HAV). Such limited vaccination coverage is a missed opportunity to prevent disease. This study was designed to develop reliable and valid theory-based quantitative measures to understand beliefs and attitudes regarding HAV vaccination among MSM. A convenience sample of 358 patrons of two gay bars in Birmingham, Alabama, completed a theory-based questionnaire. Data were randomly split into two groups. Exploratory factor analysis (EFA) was performed on the first split-half sample to identify factor structure using standard principal component analysis. Confirmatory factor analysis (CFA) was performed on the remaining half sample using structural equation modeling. EFA revealed five scales measuring beliefs about HAV vaccination, including: perceived barriers and benefits associated with HAV vaccination; perceived severity and susceptibility related to hepatitis A infection; and perceived self- efficacy to complete the two-dose vaccine series. CFA revealed acceptable absolute model fits for four scales and excellent comparative model fits for all five scales. Multivariable analysis further validated the scales. Although the results should be tested further, these findings propose standardized measures that may be useful in assessing the beliefs and attitudes of MSM towards HAV vaccination to guide intervention design and evaluation.