Introduction and Objective. Studies on volunteering concern mainly the population aged over 16, and the results refer mainly to Western Europe. Adolescent volunteering in Eastern European countries is relatively understudied. The aim of the study was to investigate and discuss the scale of this phenomenon in Poland, the predictors of being a volunteer, and factors which explain how much time adolescents spend volunteering. Materials and method. The study was conducted on a representative group of 3,545 respondents aged 14-15. 26.6% of the surveyed adolescents were involved in volunteering in the 12 months preceding the study. Results. The probability of being a volunteer is explained by contextual factors (higher regional income per capita and higher unemployment rate decrease this probability, whereas it increases by living in a city), family factors (father's work in agriculture and more children in the family), individual factors (higher self-esteem of physical fitness and less helplessness). The amount of time devoted to volunteering is explained by contextual factors (the higher the income from agriculture), family factors (mother's work in agriculture; mother's lower level of education), individual factors (greater self-efficacy, lower feeling of helplessness). Volunteering undertaken because of a passion for volunteering is associated with longer volunteering time, while undertaken because of the desire to be liked and respected -with shorter volunteering time. Conclusions. The results are of practical importance, as they show the possibility to promote adolescents' volunteering