Occupational therapy practices in Turkey are increasing each year, but rehabilitation practitioners working in the occupational therapy field have limited instruments. The aim of this study was to analyze the validity of the Turkish version of the Occupational Self Assessment (OSA), which is based on the Model of Human Occupation. The data were analyzed using exploratory and confirmatory factor analyses to determine construct validity. The Turkish OSA was administered with the World Health Organization Quality of Life-Old (WHOQOL-OLD) and the Functional Autonomy Measurement System (SMAF) to 117 elderly individuals to determine convergent validity. The Turkish OSA has acceptable construct validity scores (exploratory and confirmatory factor analyses). SMAF and WHOQOL-OLD Scales showed a moderately significant relationship with OSA competence total scores (p < .01). The results indicate that the OSA is a valid instrument for determining occupational competence and values in elderly Turkish individuals.