Purpose: The purpose of the current study is to adapt the Keele Assessment of Participation into Turkish to assess the participation of individuals aged 50 and over and to conduct its validity and reliability studies Method: The study included 150 individuals between the ages of 50 and 78 who came to Izmir Palmiye Shopping Center between February 2018 and April 2018, who could read and write in Turkish. All the participants were administered the Turkish version of Keele Assessment of Participation, Socio-demographic Questionnaire Form, Impact on Participation and Autonomy, Reintegration to Normal Living Index and Short Form 36 Quality of Life Questionnaire. For the reliability, test-retest reliability, item-total correlation coefficient, Kuder Richradson-20 and Cronbach’s Alpha (α) analyses were conducted. For the construct validity, exploratory factor analysis and confirmatory factor analysis were conducted and for the concurrent validity, its correlations with Impact on Participation and Autonomy, Reintegration to Normal Living Index and Short Form 36 Quality of Life Questionnaire were examined. Results: For the reliability, the test-retest correlation coefficient was found to be r=0.631; p<0.01, Cronbach’s Alpha coefficient was found to be 0.655, Kuder Richardson-20 coefficient was found to be 0.655 and item-total score correlation coefficients were found to be ranging from 0.232 to 0.506. Exploratory factor analysis revealed that the questionnaire has a single factor. Confirmatory factor analysis confirmed that the factor loadings of the questionnaire are suitable. In the concurrent validity, the highest correlation with the Turkish version of Keele Assessment of Participation was found for, Impact on Participation and Autonomy’s sub-group of Impact on Participation and Autonomy 1.5 (r=-0.467; p<0.001). Conclusion: Turkish version of Keele Assessment of Participation was found to be valid and reliable measurement tool to be used to assess the social participation of individuals aged 50 and over.