Ko Phi Phi Don (Thai: เกาะพีพีดอน, pronounced [kɔ̀ʔ pʰīː pʰīː dɔ̄ːn]) is the largest of the Phi Phi Islands, in Thailand. The islands are administratively part of Krabi province. It is the only island in the group with permanent inhabitants.

Like the other islands in the group, Ko Phi Phi Don is a non-volcanic island largely made of limestone. It is almost separated into two islands, but a strand of flat land connects them. On this strand lies the largest town on the island, as well as most of the resorts.