Doem Bang Nang Buat (Thai: เดิมบางนางบวช, pronounced [dɤ̄ːm bāːŋ nāːŋ bùa̯t̚]) is a district (amphoe) in the northern part of Suphan Buri province, central Thailand.

In the past, Nang Buat District covered a large area.

Prince Damrong Rajanubhab and the governor of Suphan Buri agreed to separate the northernmost part and then created a new district named Doem Bang on 16 May 1911.

[2] Its name literally means 'formerly place of ordained lady', according to folklore from the Sukhothai period.

The district is divided into 14 subdistricts (tambons), which are further subdivided into 121 administrative villages (mubans).