Pak Phli (Thai: ปากพลี, pronounced [pàːk pʰlīː]) is a district (amphoe) in the eastern part of Nakhon Nayok province, central Thailand.

The area was formally recognized by the government and classified as Tambon Khao Yai within Pak Phli District.

After an attempt to capture the fugitives in the area, in 1932 the villagers were relocated into the plains some 30 km away and the tambon status was cancelled.

In 1959 the then-Prime Minister of Thailand, Marshall Sarit Thanarat, ordered the Ministry of Agriculture and the Ministry of the Interior to create a process whereby national parks could be established and Khao Yai National Park, established in 1962 in this area, would adopt the name of the former tambon.

There are further seven subdistrict administrative organizations - SAO (ongkan borihan suan tambon - o bo tjo).