Namtok Chet Sao Noi National Park (Thai: อุทยานแห่งชาติน้ำตกเจ็ดสาวน้อย) is a national park in Thailand, with a total area of 26,238 rai ~ 42 square kilometres (16 sq mi) covering Muak Lek district, Wang Muang district, Saraburi province and Pak Chong district, Nakhon Ratchasima province.

Namtok Chet Sao Noi or Chet Sao Noi waterfall (literally: "seven little girls waterfall") is a small and beautiful waterfall. The waterfall flows along a stream and has seven tiers (hence the name seven little girls), but there are many different stories about the waterfall names. The height of each tier is approx four m (13 ft), with spacious, shaded swimming areas available underneath.

It has been upgraded from the forest park to be the 129th national park of Thailand on 26 December 2016 and is the first site in the King Rama X's reign.

• Namtok Chet Sao Noi
• Muak Lek Creek
• Tree Tunnel The tree tunnel on the bend of Thailand Route 2089 (Muak Lek–Wang Muang) making it shady to be over 200 m (656 ft) long.

Namtok Chet Sao Noi is covered in tropical rain forest, including such species as Pterocarpus macrocarpus, Sterculia foetida, Bombax ceiba, Garuga pinnata, Senna garrettiana, Senna garrettiana, Ficus carica, Holarrhena pubescens and Fernandoa adenophylla.

Animal species include serow, jackal, marten, small civet, porcupine, palm civet, hare, ground squirrel, striped squirrel, flying squirrel, mongoose, pangolin, black baza, palm swift, shrike, snail-eating turtle, house gecko, monitor lizard, water monitor, python, birdwing etc.

• List of national parks of Thailand
• List of Protected Areas Regional Offices of Thailand

• "Namtok Chet Sao Noi National Park" (PDF). Department of National Parks, Wildlife and Plant Conservation.