The aim of the study was to develop a measure identifying specific skill sets of effective witness protection (WP) officers. Two representative groups produced a job analysis for WP officers from which we generated a pool of items forming a Behavioural Observation Scale (BOS). Supervisors of 50 Australian WP officers (40 men) completed the BOS. Exploratory factor analysis produced a 38-item BOS resolving into three factors, Policing skills, Partition skills and Interpersonal skills, explaining > 69% of the variance with excellent internal consistency of >.90. The BOS represents a reliable and valid tool for selecting WP officers.