Standardized assessment measures are important for accurate diagnosis of mental health problems and for treatment planning and evaluation. However, little is known about youth mental health providers' typical use of standardized measures across disciplines and outside the context of evidence-based practice initiatives. A multidisciplinary national survey examined the frequency with which 674 youth mental health providers administer standardized and unstandardized measures, and the extent to which organizational (i.e., implementation climate, rigid hierarchical organizational structure) and provider (i.e., attitudes toward standardized assessment measures, highest degree, practice setting) characteristics are associated with standardized measure use. Providers used unstandardized measures far more frequently than standardized measures. Providers' perceptions (a) that standardized measures are practical or feasible, (b) that their organization supports and values evidence-based practices, and (c) that their organization has a rigid hierarchical structure predicted greater use of standardized measures. Working in schools predicted less frequent SMU, while working in higher education and other professional settings predicted more frequent SMU. Standardized measures were not routinely used in this community-based sample. A rigid hierarchical organizational structure may be conducive to more frequent administration of standardized measures, but it is unclear whether such providers actually utilize these measures for clinical decision-making. Alternative strategies to promote standardized measure use may include promoting organizational cultures that value empirical data and encouraging use of standardized measures and training providers to use pragmatic standardized measures for clinical decision making.