This study compares co-operative sectors in Scotland with those of three similar sized countries: Switzerland, Sweden and Finland. The economic contribution of co-operatives in Scotland has historically been below that of these comparable European countries. The study asks why the comparator countries are so much more successful, what we can learn about how to do co-operative development, and which of the success factors are replicable in Scotland. It aims to help Co-operative Development Scotland to understand the determinants of success, make informed decisions on how to promote the co-operative sector, and advise policymakers about what works.