Background and Purpose: Since positive thinking has a major impact on many aspects of life, the purpose of this study was to investigate the effect of positive-thinking education on the perceived competency and social skills of the orphan and mistreated children of 10 to 12 years old.

Method: The method of the study was quasi-experimental and one-sample design with pre-test and post-test. The statistical population included all the female orphans and mistreated children between the ages of 10 and 12 from Rasht in 2016 that among them 10 children were selected using convenience sampling. The research tools were social skills questionnaire for teachers (Gresham and Elliot, 1990) and Children's competency perception questionnaire (Harter, 1982). Positive thinking was trained in 14 sessions of 90 minutes to the sample group. Data analysis was performed using Cohen's coefficient and Hedges coefficient.

Results: The results of this study showed that positive-thinking education could increase the perceived competence and social skills of children and the subjects participating in the post-test had significantly higher perceived competence and social skills (P < 0.01).

Conclusion: In sum, the results of this study confirm the usefulness and effectiveness of positive thinking in increasing the perceived competency and social skills of the orphan and mistreated children.