German federal states and municipalities have engaged in decentralised development co-operation (DDC) since the 1950s. Germany provides over half of total official development assistance (ODA) in the world that is channelled as DDC. However, most of this support remains within German borders. To incentivise further international partnerships, the federal government has established dedicated programmes and financial support schemes for states and municipalities. This report presents key data on the DDC landscape in Germany and offers guidance on how to strengthen its role in enabling peer-to-peer learning and improve collaboration between German states and municipalities. It also showcases how to further raise awareness about the mutual benefits of DDC partnerships, including through better ODA data reporting and a harmonised approach to monitoring and evaluating its results across levels of government.