The current study examined the utility of the Ohio Scales, Hopefulness Scale (OS Hopefulness Scale; Ogles et al., 2004), a free multi-informant four-item measure of hopefulness used within a large statewide public mental health care system. Collectively, the six aims of this study (done for both youth- and caregiver-report versions) examined (a) the measure’s factor structure and (b) internal consistency, (c) the relationship between youth- and caregiver-reported hopefulness, (d) the measure’s relationships with numerous domains of psychopathology (e.g., depression, anxiety, delinquency) and (e) functioning, and (f) sensitivity to change. Using a sample of 986 participants, who were ethnically diverse (30.5 % multiethnic, n = 301), 61.0 % male (n = 601), with an average age of 12.74 (SD=3.46), the study found good factor structure, acceptable internal consistency, and a significant positive association between youth-reported and caregiver-hopefulness. Additionally, significant inverse relationships were found between caregiver-reported hopefulness with youth mental health problems and youth functioning; while youth-reported hopefulness was found to be significantly inversely related to youth mental health problems but not youth functioning. Finally, significant positive changes in hopefulness and significant inverse relationships with youth functioning were also evident at three-month follow up for both youth- and caregiver-reported hopefulness. The constellation of our findings demonstrates potential for this four-item measure of hopefulness to be a useful, efficient, and cost-effective tool with ethnically diverse samples, which are substantially different from samples included in previous studies of hopefulness. Implications and suggestions for future research are discussed.