This study describes the development of a social problem solving test for elementary school students (SPSTE). The SPSTE scales are performance measures of social problem-solving competence that is based on a multidimensional theoretical model of social problem solving and utilized a combined cross-situational and cognitive-behavior-analytic approach. The scales measure the social cognitive-affective aspects, specific-problem defining skills, and basic problem-solving abilities that were used by children in their interpersonal relations in their own words. The SPSTE-A (form A for the 3rd, 4th, and 5th grade students) consists of 50 items through ten interpersonal problematic situations. The SPSTE-A is structured into five subscales that were designed to assess the five dimensions of social problem-solving competence. From three preliminary samples that consist of 417 Vietnamese elementary students (3rd, 4th, and 5th grades), psychometric properties concerning the reliability and validity of the tool were reported. The results provided evidence that the SPSTE has empirically sound psychometric properties and that the scale is a promising multidimentional outcome measure of social problem-solving competence in elementary school students.