The main purpose of this research is to develop a scale for IT professional competency evaluation, which is considered crucial for outsourcing. The study compares the competencies of IT consultants and IT staff in Thailand’s banking sector. The participants were IT professionals with significant experience of IT outsourcing projects at seven leading banks in Thailand. Statistical techniques used to analyse the survey data included exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The results identified a number of differences between the competencies of IT consultants and IT staff. Among the four dimensions of IT consultant competency, the most important was coaching and customer focus skills, followed by knowledge sharing attitude, project management skills and technical lead business knowledge. IT staff competency comprised three dimensions. The most important of these was project management skills, followed by results-oriented attitude and practical business knowledge.