The aim of this study is to examine the mediating role of life satisfaction in the relationship between optimism and happiness levels of physical education teacher candidates. The research group consists of 278 physical education teacher candidates who were trained in the formation education program opened at Akdeniz University in the 2018-2019 academic year. Optimism Scale, Happiness Scale and Life Satisfaction Scale were used to collect research data. In the process of analyzing the data, Pearson correlation analysis was used first to determine the relationships of variables with each other, and PROCESS macro regression analysis was used to determine the mediating effect of life satisfaction between optimism and happiness. As a result, it can be said that life satisfaction has a mediating role in the relationship between optimism and happiness levels of physical education teacher candidates. In line with this information, considering that life satisfaction is an important psychological factor in physical education teacher candidates, it is extremely important to keep the life satisfaction levels of physical education teacher candidates, who have a primary effect on the healthy upbringing of future generations. In this context, it is recommended that relevant rule makers or managers who want to increase the quality and quality of education take this information into consideration.