Literature has shown that temperament predicts a range of childhood outcomes, including social competence, academic performance, and empathic... Show moreLiterature has shown that temperament predicts a range of childhood outcomes, including social competence, academic performance, and empathic responsiveness. Temperament also has been consistently shown to be a risk factor for psychopathology (e.g., externalizing disorders, conduct problems, anxiety, and depression). Although there is general agreement on the definition of temperament, there are still aspects of this construct that are disputed (e.g., the specific traits involved and the degree to which they are stable across development). Moreover, researchers also have developed different strategies to assess this construct, specifically parent-report and direct observation, both of which have their limitations. Despite these limitations, very few measures temperament measures utilize ecologically valid observations in naturalistic settings. The purpose of this study was threefold. The first aim was to examine the construct validity of a newly-developed behavioral observation measure of temperament through confirmatory factor analysis (CFA). The second aim was to determine if the measure was invariant across age and gender. Finally, the third aim was to assess the measures’ convergent and predictive validity. This measure was administered to 796 children across three ages (i.e.,ages 4, 5, and 6). Results from the CFAs revealed that a four-factor structure was the best fit to the data at age 4, therefore supporting configural invariance across gender for that age group. Invariance testing also showed that the measure demonstrated metric, but not scalar, invariance across gender at age 4. Finally, this study found evidence for both convergent and predictive validity for this measure. Directions for future research are also discussed. M.S. in Psychology, May 2018 Show less