This study examines the geostrategic transformations reshaping the African Sahel and their implications for Algeria’s geopolitical environment. It focuses on political change, military coups, shifting regional alliances, declining French influence, the rise of new international actors, and the emergence of the Alliance of Sahel States. Using a theoretical and analytical approach, the study links these developments to Algeria’s security, diplomatic, economic, and strategic interests. The findings show that instability in Mali, Niger, and Burkina Faso has intensified challenges related to terrorism, organized crime, irregular migration, border security, and regional cooperation. At the same time, evolving alliances and diversified partnerships create new opportunities for Algeria to reinforce its African strategic depth, diplomatic mediation, economic connectivity, and regional influence. The study concludes that Algeria’s response requires an integrated approach combining security, diplomacy, development, economic cooperation, border management, respect for sovereignty, and continuous adaptation to rapidly changing regional balances within the Sahel region.