Plaeng Yao (Thai: แปลงยาว, pronounced [plɛ̄ːŋ jāːw]) is a district (amphoe) of Chachoengsao province, central Thailand.

The minor district (king amphoe) Plaeng Yao was established on 16 October 1978 with the three tambons: Plaeng Yao, Hua Samrong, and Wang Yen from Bang Khla district.

[1] Neighboring districts are (from the west clockwise): Ban Pho, Bang Khla, Ratchasan, Phanom Sarakham, and Sanam Chai Khet of Chachoengsao Province; and Ko Chan, Phanat Nikhom, and Phan Thong of Chonburi province.

Plaeng Yao is home to Toyota's Gateway Assembly Plant.

[3] Plaeng Yao district is divided into four sub-districts (tambons), which are further subdivided into 48 administrative villages (mubans).