Isabela City is a city and the capital of the province of Basilan, in the Philippines. While administratively, the island province of Basilan is part of the Autonomous Region in Muslim Mindanao (ARMM), Isabela City itself is in not part of this region and is placed under the Zamboanga Peninsula region. The city is located on the northern shore of Basilan. Across the Basilan Strait to the north is Zamboanga City.

Isabela City, like the rest of the province, has seen some of the fiercest fightings between government troops and the Abu Sayyaf, an Islamic separatist group.