Behavioral event interviews were conducted with twenty-three organization development practitioners ranging in experience from two to more than twenty years and twenty-two client organizations from public and private sectors to generate a set of consultant behaviors judged to be effective and ineffective during organizational interventions. Six general dimensions of competency and a list of fourteen important behavior classes emerged from coding and content analyses of the behavioral events by independent observers. Some behaviors were judged to belong to more than one competency category, although five of the six clusters were dominated by particular behaviors. These data provided the basis for developing a behavior observation scale for assessing consultant skills and intervention effectiveness. This behavioral perspective holds promise for improving organization development training programs and for on-going professional development among consultants, as well as for enhancing client understanding of co...