Although there is increased interest in social and emotional competence and mental health in Croatia, there are currently limited measurement options available for early childhood settings. Thus, the SSIS SEL Brief Scales (SSIS SELb), an efficient measure of social and emotional learning competencies developed in the United States, was translated to Croatian and used by 49 early childhood educators to rate a sample of 685 children (average age 4.3 years) from several counties in Croatia. Regarding measurement invariance, the final model cohered substantially with a CASEL-inspired framework. Overall reliability was also high especially for the SEL Composite (α = .94), with notably lower reliability for subscales. Regarding cross-group concurrent validity, concurrent coefficients were largely similar across age and gender, but there were regional differences in validity. Likewise, validity correlations were in line with expectations, with moderate relationships observed between the SSIS SEL Composite and Child and Youth Resilience Measure scores. In sum, the high level of reliability provided a foundation for applied and research usage of the Croatian SSIS SELb, although further validation research will continue to be necessary before widescale implementation. Limitations to the study are discussed and also point to needed additional research before utilizing the Croatian translated SSIS SELb for applied decisions with young children.