The current study reports on the process of developing a self-assessment instrument for vocational education students' generic working life competencies. The instrument was developed based on a competence framework and in close collaboration with several vocational education teachers and intermediary organisations offering various human resource services. A first version of the questionnaire was presented to 26 students and 5 recent graduates who were asked to comment on the items. The pilot version of the questionnaire was completed by 826 students. Half of the data were used to explore the structure of the questionnaire (n?=?413) and the other half were used to confirm the structure (n?=?413). The results showed that 8 factors could be distinguished. Further analysis reduced this to 7 usable factors: empathy, listening, assertiveness, professional attitude, problem solving, cooperation ability and, planning and prioritising. The revised questionnaire containing 44 items was tested a second time to determine the stability and measurement invariance of the instrument. In total, 456 students from the first sample completed the questionnaire. The structure was confirmed and measurement invariance across students with and without working experience was established.