The Questionnaire for Eudaimonic Well-Being (QEWB) was developed to measure well-being in a manner consistent with how it is conceptualized in eudaimonist philosophy. Aspects of eudaimonic well-being assessed by the QEWB include self-discovery perceived development of one's best potentials a sense of purpose and meaning in life intense involvement in activities investment of significant effort and enjoyment of activities as personally expressive. The QEWB was administered to two large ethnically diverse samples of college students drawn from multiple sites across the United States. A three-part evaluation of the instrument was conducted: (1) evaluating psychometric properties (2) comparing QEWB scores across gender age ethnicity family income and family structure and (3) assessing the convergent discriminant construct and incremental validity of the QEWB. Six hypotheses relating QEWB scores to identity formation personality traits and positive and negative psychological functioning were evaluated. The internal consistency of the scale was high and results of independent CFAs indicated that the QEWB items patterned onto a common factor. The distribution of scores approximated a normal curve. Demographic variables were found to predict only small proportions of QEWB score variability. Support for the hypotheses tested provides evidence for the validity of the QEWB as an instrument for assessing eudaimonic well-being. Implications for theory and future research directions are discussed.