The purpose of this study was to examine the reliability and validity of outcome likelihood, outcome value, and outcome expectancy using data collected from students in secondary school physical education classes. Dependent measures were examined for construct, concurrent, and predictive validity, as well as internal and temporal reliability. The results of the investigation indicated the following. First, confirmatory factor analyses for the dependent variables (outcome likelihood, outcome value, outcome expectancy) revealed a suitable fit of the data with a hypothesized factor structure. Second, significant associations between these variables and other personal beliefs and values provided sound evidence for the concurrent validity of outcome likelihood, outcome value, and outcome expectancy. Third, results of regression analyses revealed that outcome likelihood and outcome value had strong predictive validity in predicting physical activity behaviors. Finally, the internal reliabilities of self-report scales for the outcome likelihood, outcome value, and outcome expectancy over a three-semester period were satisfactory. The temporal reliabilities were also acceptable. (Contains 3 tables.)