Bang Nam Priao (, ) is the northwesternmost district (amphoe) of Chachoengsao province, central Thailand.
The old location of the district center of Bang Nam Priao was in Ban Ton Samrong, Bang Khanak Subdistrict. In 1905 the government built the first district office in Bang Nam Priao. In 1952 the government built a new office on the north bank of Khlong Bang Khanak (the lower reaches of the Khlong Saen Saeb). The present district office was built in 1997.
Its name, "Bang Nam Priao", literally means "the place where the water tastes sour". It is said that in the past the soil in this area was naturally acidic, which caused the water to have a sour taste as well.
The population of Bang Nam Priao is a mix of people of various races and religions, including Thai Buddhists, Thai Chinese, Muslims, Mons and Christians.
Neighbouring districts are (from the southeast clockwise): Khlong Khuean, Mueang Chachoengsao of Chachoengsao Province; Nong Chok of Bangkok; Lam Luk Ka of Pathum Thani province; Ongkharak of Nakhon Nayok province; and Ban Sang of Prachinburi province.
The important water resources are the Bang Pakong River and Khlong Saen Saeb.
Bang Nam Priao is divided into 10 subdistricts (tambons), which are further subdivided into 148 administrative villages (mubans).
There are six subdistrict municipalities (thesaban tambon) in the district:
There are eight subdistrict administrative organizations (SAO) in the district: