The aim of this research was to develop a scale in order to measure psychological well-being in preschool children. Three hundred and seventy five to six year old children participated in the research from 5 regions of Tehran, using accidental sampling method. The participants were individually interviewed with the Well-Being in Preschool Children Scale, and their teachers completed Rutter’s Child Behavior Questionnaire about each of them. Data was analyzed with both exploratory and confirmatory factor analysis methods using WLSMV and GEOMIN oblique rotation, to examine factorial structure. Samejima’s graded response model was used to access psychometric features of the items. Test-retest reliability was measured and Pearson’s correlation was also used to assess divergent and convergent validity. Findings revealed that this scale has 3 main factors: self-concept, life satisfaction and resilience. The validity and reliability of the scale is also satisfactory. The well-being indicators in this scale are consistent with previous research on components of well-being in children. In addition there is a negative correlation between psychological well-being and behavioral problems, which is also illustrated in previous research.