Assessment is an integral component of treatment. However, prior surveys indicate clinicians may not use standardized assessment strategies. We surveyed 1,510 clinicians and used multivariate analysis of variance to explore group differences in specific measure use. Clinicians used unstandardized measures more frequently than standardized measures, although psychologists used standardized measures more frequently than nonpsychologists. We also used latent profile analysis to classify clinicians based on their overall approach to assessment and examined associations between clinician-level variables and assessment class or profile membership. A four-profile model best fit the data. The largest profile consisted of clinicians who primarily used unstandardized assessments (76.7%), followed by broad-spectrum assessors who regularly use both standardized and unstandardized assessment (11.9%), and two smaller profiles of minimal (6.0%) and selective assessors (5.5%). Compared with broad-spectrum assessors, unstandardized and minimal assessors were less likely to report having adequate standardized measures training. Implications for clinical practice and training are discussed.