Research Doctorate - Doctor of PhilosophyThere were two major aims in the current study. The first was to investigate the psychometric properties of the Thai Social and Emotional Skill Rating Scale (TSESRS) developed by the author. The measurement model of this material is a three factor model containing social skills, emotional skills, and social-cognitive skills. These factors were measured from eight indicators. Data were collected from 685 lower secondary school students who were studying in schools under the jurisdiction of the Phatthalung Educational Area Office, Thailand. Materials used in this phase were the trial version of the TSESRS, the Thai Emotional Skill Scale (TESS) and the Thai Social Skill Scale (TSSS). The evidence suggested that the following psychometric properties of the TSESRS are within the acceptable cut-off levels: item-validity, item-reliability, item-discrimination, test-reliability, construct validity, criterion related validity, and factorial validity. It was also found that a three factor model was the best fitting model. These results suggest that the TSESRS measures three distinct latent constructs, that is, social skills, emotional skills, and social-cognitive skills. The second aim was to examine the structural relationship of three exogenous variables, that is, social skills, emotional skills, and social-cognitive skills with two types of behaviour problems, that is, internalizing and externalizing problems. Data for this phase were collected from 951 students drawn from the same population as the first phase. Materials used for data collection were the TSESRS and the Thai version of the Youth Self-Report (YSR). The results revealed that among the three exogenous variables, social-cognitive skills was the only significant predictor of both internalizing and externalizing problems. The relationship between social-cognitive skills and two types of behaviour problems was negative. This means that the higher a students’ social-cognitive skills, the lower their level of internalizing and externalizing problems. The indicators of social cognitive skills were emotion control, problem solving, and decision making skills. This finding has important implications for dealing with behaviour problems in Thai students. Thai teachers or educators may use these findings for selecting from available programs or for developing new programs