One hundred twenty-two undergraduate students at the University of North Texas were administered several different optimism scales and also measures of similar constructs such as hope. Results indicated that most measures of optimism show only low to moderate intercorrelations with other measures of the same construct. Additionally, factor analysis confirmed that the measures of optimism actually appear to be assessing multiple factors and not necessarily optimism alone. Implications of the present study include the necessity of individual researchers to be familiar with the specific measure of optimism used in a given study as scores on differing measures of optimism may actually be providing very different information.