The present field study was designed to examine the influence of organizational frustration and locus of control on emotional and behavioural reactions to frustrating conditions. Data were collected by questionnaire from 160 employees from all levels of a community mental health facility. As hypothesized, organizational frustration was found to be positively related to interpersonal aggression, sabotage and withdrawal. Subgroup moderator analysis supported the hypothesized moderating relationship of locus of control on the perceived frustration behavioural reactions relationship. These results suggest that persons with an external locus of control are more likely to respond to frustration with counterproductive behaviour than persons with an internal locus of control. The implications of these findings for organizations are discussed.