["The World Economy, EarlyView. ", "\nABSTRACT\nThis study investigates whether South–South cooperation delivers tangible economic benefits by examining the impact of the BRICS Plus platform on the economic development of participating countries. Using national‐level panel data for 125 countries from 2009 to 2022 and applying a staggered Difference‐in‐Differences approach, we find that BRICS Plus participation is associated with an average annual GDP per capita growth rate increase of approximately 3.42% compared to non‐participating countries on the same continent. Mechanism analysis suggests that the positive effect is driven by enhanced foreign direct investment, improvements in trade balances, and expanded financing channels, with India and China playing leading roles through investment, and South Africa contributing through regional financing. Participation is also linked to improved governance and reductions in civil conflicts but shows no significant increase in aid inflows from other international organizations. Heterogeneity analysis indicates that the positive economic effects are concentrated in Asian and African countries, among low‐ and lower‐middle‐income economies with higher agricultural shares, and in countries with stronger initial infrastructure. Overall, the results provide empirical support for the developmental potential of institutionalized South–South cooperation through platforms like BRICS Plus.\n"]