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.