Despite their importance to evidence-based assessment, standardized assessments remain underutilized by mental health practitioners in practice. The underutilization has been attributed to a lack of appreciation of the importance of standardized assessments, lack of knowledge of standardized assessments, and practical barriers to implementation. This study sought to gather the first descriptive data on alcohol and other drug (AOD) practitioners’ attitudes toward, and knowledge and self-reported use of, standardized assessments. Practical barriers to implementation in initial assessment and progress monitoring were also assessed. Ninety-nine Australian AOD practitioners recruited via newsletters of national representative bodies and practitioner networks completed an online survey. While practitioners’ attitudes towards using standardized assessments for initial assessment and progress monitoring were generally positive and consistent with other populations of health practitioners, assessments remained underutilized in practice. Most AOD practitioners did not consider standardized assessments to be feasible to implement. The current findings highlight the importance of practical barriers, particularly organization-level barriers, in the underutilization of standardized assessments in AOD practice. Findings support an extension of dialogue surrounding evidence-based practice beyond treatment selection to include assessment practices at a more general level. The present study offers a starting point from which efforts to improve practitioner compliance with evidence-based best practices can be conceived, designed, and implemented.