This study aimed to evaluate the effects of the FunFRIENDS protocol on anxiety symptoms, internalizing problems and prosocial behavior in 4- to 5-year old children. Participated of this study 43 children with an allocation ratio of 1:1 between groups (Intervention Group [IG], N = 21; Control Group [CG], N = 22) from a public school in the city of Sao Paulo participated in the study. Behaviors were evaluated by using standardized questionnaires (PAS, CBCL, SDQ, SCBE) assessing the behavioral profile of the children at three different periods; baseline (T0), one month (T1) and three months (T2) after the intervention. It was observed a reduction in the intensity of anxiety symptoms in the IG after the intervention but with no significant effect. Overall, there were no significant differences between the IG and the CG in most behaviors on all periods evaluated. On both Intention-to-Treat analyses also it was not detected significant effects of the intervention. This is the first Brazilian study evaluating the effects of FunFRIENDS program and the implications of these findings are discussed and its significance for future research.