While migration from the South to the North has traditionally received greater attention, there has been a growing interest in analysing migration within the countries of the South in recent years. This publication synthesizes the main findings of a series of studies carried out by the Migration Observatory (ACP) in relation to South-South migration. The report covers the thematic areas of labour mobility, the impact of South-South migration on development, diaspora and remittances, migration and internal displacement, and irregular migration and return, as well as some cross-cutting issues, such as human rights and environmental migration.