The school, with its activities as an upbringing and educational institute, influences all segments of a pupil's effective development. Besides teaching as its basic activity, the school should take over part of the care and responsibility for the pupil's free time and "use" it for "prolonged" upbringing activity. Today children and young people "spend" their free time on the Internet and little or almost no time in the development of social competences. Confronted with technology as an inevitable challenge of the present day, we are also confronted with new issues in our upbringing and education practice. Due to unpreparedness in participating in joint activities and the impossibility of communication, pupils show numerous manifestations in behavioral disorder, which often determine school success. Participation in extracurricular activities reduces the action area of risk factor in children and youth in their free time, which effects school success in particular. Numerous researches have confirmed how the engagement of pupils in extracurricular activities is one of the factors that influences school success. In Croatia, extracurricular activities are quite neglected for numerous reasons. It is necessary to bring them back to the school and to modernize them and make them challenging and attractive for pupils. Research results on 970 elementary school pupils of Zadar and Šibenik-Knin counties are elaborated in this work. Their participation in extracurricular and out-of-school activities and their connection to school success was examined. The results confirm the presumption that children who participate in extracurricular and out-of-school activities achieve better school success.