This study was conducted to investigate the depressive state and loneliness in a total of 219 male adolescents between the ages 11 and 13 who were registered at the summer school of the Vezirköprü Provincial Directorate of Youth Services and Sports based on whether or not they participated in recreational and sports activities during the summer holiday. One hundred and fifteen of the participants participated in recreational and sports activities organized during the summer, while 104 did not. Information about the depressive states of the participants was collected via the Beck Depression Scale, while information about their loneliness was collected with the UCLA Loneliness Scale. High total scores on both scales indicated that depression and loneliness levels were high. The Cronbach's alpha internal consistency coefficient was calculated to determine the reliability of the answers given by the participants to the items of Beck Depression Scale and UCLA-LS. In the statistical assessment of the research results, it was found that the error terms were not normally distributed (P<0.05). Thus, the differences between the group that participated in recreational activities and the group that did not were shown via a Mann-Whitney U-test. In addition, the association between the total scores on both scales was calculated using Kendall's tau b correlation coefficient. At the end of the study, the Beck Depression scores of the adolescents who did not participate in any recreational or sports activities during the summer holiday (13 weeks) were found to be significantly higher than the scores of those who did. Thus, while the depression levels of individuals who did not participate in recreational or sports activities were high, the levels of individuals who regularly participated in these activities were low. Similarly, the loneliness scores of individuals also differed based on participation in these activities. The loneliness scores of adolescents who did not participate in the related activities were found to be significantly higher than those who did. In short, the reason for these low levels of depression and loneliness following participation in sports activities is understood to result directly from participation in these activities. Also, a strongly positive significant association was found between the Depression and Loneliness Scale scores of adolescents who did engage in sports. An increase was seen in the Beck Depression scores of the participants as their loneliness scores increased. In other words, as Beck Depression scores increase, so do the levels of loneliness. Thus, engaging in regular recreational and sports activities over extended periods of time can be said to be effective in eliminating the depressive and lonely feelings of adolescents. Educational institutions should include such programs within regular education.