Purpose: The Purpose of the present study was Examining the effectiveness of problem solving skills training on psychological Hardiness and cognitive emotion regulation strategies of high school students in Tehran. Methodology: Method of research was an applied one in terms of purpose and a quasi-experimental in terms of data collection with pretest-posttest, control group, random assignment of subjects. Statistical population included all female students studying in Tehran in 1396-97. Forty students were assigned through convenience sampling. That is 40 students were split into two groups, assigning 20 to each, one group as control and the other as experiment group. The experiment was trained problem solving (8 sessions, lasting 90 minutes each); the control group received no treatment(training). To collect data, the Psychological Hardiness Scale (Kobasa,1979) and cognitive emotion regulation strategies (Garnefski et al, 2001) were used. Data analysis based on the data obtained from the questionnaires through SPSS-v22 was done at 0.05 significance level in two parts, descriptive and inferential (Covariance analysis). Findings: The Results showed that problem solving skills training affected on adolescent’s psychological hardiness and cognitive emotion regulation strategies (p<0.001). Conclusion: Therefore, Problem solving skills training can be used as an effective intervention to improve psychological hardiness and cognitive emotion regulation strategies in high school students.