Background Quality clusters were introduced as a quality improvement concept in Danish general practice in 2018. This new concept anchored quality improvement in local clusters managed by general practitioners (GPs). Objectives To describe the cluster organization and GPs' self-reported benefits of participating in them and explore the associations between cluster organization and self-reported benefits. Methods A national survey in Danish general practice gathering information about cluster organization (cluster size, cluster meetings, participants, and content) and GPs' self-reported benefits (overall benefit, internal changes in the clinic, and improved external collaboration). Results One hundred and eight (95%) clusters and 1,219 GPs (36%) were included. Cluster size varied from 10 to 68 GPs (34 GPs on average). Approximately 70% of GPs reported moderate to very high overall benefit from cluster participation. Most GPs experienced changes in their clinic organization (68%), drug prescriptions (78%), and patient care (77%). Collaboration was reported improved between the GPs (86%), municipality (50%), and hospital (36.2%). GPs in clusters with 3-6 planned meetings per year (odds ratio [OR] 1.9; confidence interval [CI] 1.3-2.9), mixed meeting types (OR 1.7; CI 1.2-2.4), group work (OR 1.7; CI 1.1-2.5), and use of guidelines in their meetings (OR 1.8; CI 1.3-2.4) had statistically significantly higher odds for reporting overall benefit of participating in clusters compared with GPs in clusters without these characteristics. Conclusions Frequent and active meetings with a relevant meeting content are positively related to GPs' perceived benefits and with improved collaboration between GPs in the clusters. There seems to be a potential for developing collaboration with other healthcare providers.