Enjoyment is one of the most important factors for the maintenance of regular physical activity. The present study investigated if cooperative games in physical education classes (grades 6-9) can increase students' enjoyment of physical activity. Data were collected in a quasi-experimental study employing a two-group design with repeated measures and randomization of classes to conditions. The total sample consisted of N = 285 students from regular schools in Germany aged 10 to 16 years (Mage = 12.67 years, SD = 1.10; 48.4% female). We found that cooperative games led to a higher perceived enjoyment in physical education classes (F(1) = 3.49, p = .063, ηp2 = .012), increased the feeling of how strong students felt related to each other (F(1) = 4.38, p = .037, ηp2 = .016), and facilitated feelings of perceived competence in physical education class (F(1) = 6.31, p = .013, ηp2 = .022). In addition, social relatedness and perceived competence partly mediated the effect of cooperative games on enjoyment. The findings indicate that systematically designed cooperative games can help foster enjoyment in physical education classes.