Song Phi Nong (, ) is the southernmost district (amphoe) of Suphan Buri province, central Thailand.
The district was established in 1896. In the past the area of the district included U Thong district. The district office was moved away from the Song Phi Nong canal to the present location in 1964 because the old location was prone to flooding.
Its name, Song Phi Nong, means "two siblings." Presumably, it refers to the confluence of two watercourses, Tha Wa and Chorakhe Sam Phan, before they flow into the Tha Chin River. Another explanation comes from a folk tale about two brothers or two elephants who are siblings.
Neighbouring districts are (from the north clockwise): U Thong and Bang Pla Ma of Suphan Buri Province; Lat Bua Luang of Ayutthaya province; Bang Len and Kamphaeng Saen of Nakhon Pathom province; and Tha Maka and Phanom Thuan of Kanchanaburi province.
The main water resource of the district is the Tha Chin River or Suphan River.
Song Phi Nong is divided into 15 subdistricts (tambons), which are further subdivided into 140 administrative villages (mubans).
There is one town (thesaban mueang) in the district:
There is one subdistrict municipality (thesaban tambon) in the district:
There are 14 subdistrict administrative organizations (SAO) in the district: