Scripting computer-supported collaborative learning has been shown to greatly enhance learning, but is often criticized for hindering learners' agency and thus undermining learners' motivation. Beyond that, what makes some CSCL scripts particularly effective for learning is still a conundrum. This meta-analysis synthesizes the results of 53 primary studies that experimentally compared the effect of learning with a CSCL script to unguided collaborative learning on at least one of the variables motivation, domain learning, and collaboration skills. Overall, 5616 learners enrolled in K-12, higher education, or professional development participated in the included studies. The results of a random-effects meta-analysis show that learning with CSCL scripts leads to a non-significant positive effect on motivation (Hedges' "g" = 0.13), a small positive effect (Hedges' "g" = 0.24) on domain learning and a medium positive effect (Hedges' "g" = 0.72) on collaboration skills. Additionally, the meta-analysis shows how scaffolding single particular collaborative activities and scaffolding a combination of collaborative activities affects the effectiveness of CSCL scripts and that synergistic or differentiated scaffolding is hard to achieve. This meta-analysis offers the first counterevidence against the widespread criticism that CSCL scripts have negative motivational effects. Furthermore, the findings can be taken as evidence for the robustness of the positive effects on domain learning and collaboration skills.