Zamboanga Peninsula, officially designated as Region IX, is an administrative region in the Philippines occupying the western section of Mindanao. It covers 3 provinces, namely, Zamboanga del Norte, Zamboanga del Sur, and Zamboanga Sibugay, as well as 1 highly urbanized city (Zamboanga City) and the component city of Isabela. The regional center is the City of Pagadian.

Its population as determined by the 2020 Census was 3,875,576. This represented 14.76% of the overall population of the Mindanao island group, or 3.55% of the entire population of the Philippines. Based on these figures, the population density is computed at 229 inhabitants per square kilometer or 594 inhabitants per square mile.