Zamboanga Peninsula (Cebuano: Lawis sa Zamboanga; Chavacano/Spanish: Peninsula de Zamboanga; Filipino: Tangway ng Zamboanga), designated as Region IX, is an administrative region in Mindanao, Philippines. It consists of the provinces of Sulu, Zamboanga del Norte, Zamboanga Sibugay and Zamboanga del Sur, and the cities of Isabela and Zamboanga City.
The region was previously known as Western Mindanao. Pagadian serves as the regional center, while Zamboanga City is the region's commercial and industrial center.