According to C. Carver and M. Scheier, dispositional optimism is a cognitive disposition (personal trait) which includes general expectations about the future or person’s tendency to believe that there will be more positive events in the future than negative ones. Many researches showed that optimism as positive expectations is related to better indicators of physical health, psychological well-being, better interpersonal relationships. The main posited mechanism of these relations is the influence of optimism on motivation that manifests itself in readiness of optimists to make efforts to solve problems that occur in their lives. The paper presents the results of approbation of the LOT-R, revised version of dispositional optimism questionnaire developed by M. Scheier, C. Carver and M. Bridges. Validation was realized in two studies — in the sample of undergraduate and postgraduate students of different universities (n = 406) and in the representative Russian sample (N = 1509). Both of these studies demonstrated a high reliability of the questionnaire (a = 0.78). Using confirmatory factor analysis, the two-factor structure (including optimism factor and style of answer factor) was confirmed. The validity of the Russian version of LOT-R is supported by substantive correlations with indicators of psychological well-being and moderate but statistically significant correlations with indicators of optimistic attributional style. The construct validity of the test is also supported by correlations with indicators of self-regulation, hope, and hardiness. Detailed information about the association between dispositional optimism and sociodemographic variables (gender, age and educational level) are presented. The statistical norms are provided. The LOT-R questionnaire provides wide opportunities for Russian psychologists to continue the research on dispositional optimism and its impact on health, well-being, performance, and interpersonal relationships.