The current study aimed to reveal the differences between those with kindergarten qualifications and those with other qualifications from kindergarten teachers in both mental flexibility (adaptive flexibility - automatic flexibility), and psychological happiness (happiness of life - job happiness), as well as the differences between them in decision-making, as it seeks The current study reveals the correlation between these three variables among kindergarten teachers, and the researcher used the descriptive approach, and the study sample consisted of a community of kindergarten teachers in Sharkia Governorate. The number of members of the current study sample reached (220) kindergarten teachers. To measure the variables included in the current study, the following were designed and used: Psychometric Happiness Scale (prepared by the researcher) Decision-making scale (prepared by the researcher) Mental Flexibility Scale Prepared (Prof. Dr. Salah Sharif, 2011) The results of the study reached: - There are statistically significant differences between the averages of the grades of kindergarten teachers (kindergarten qualification - other qualifications) in the measure of mental flexibility and its dimensions (adaptive flexibility - automatic flexibility) where those differences are directed in favor of teachers with qualifications of kindergarten colleges. - There are statistically significant differences between the averages of the grades of kindergarten teachers (experience less than five years - experience more than five years) in the measure of mental flexibility and its dimensions (adaptive flexibility - automatic flexibility) where those differences are directed in favor of teachers with more experience. - There is a positive correlation between the averages of the grades of kindergarten teachers in the measure of mental flexibility and both measures of psychological happiness and decision-making. - The higher the mental flexibility, the higher the psychological happiness of the kindergarten teachers. - The higher the mental flexibility, the higher the ability to make decisions among kindergarten teachers. In light of these results, the researcher proposed a set of recommendations and proposed research that can be taken in the field of kindergarten.