Long (Thai: ลอง, pronounced [lɔ̄ːŋ]) is a district (amphoe) in the western part of Phrae province, northern Thailand.

Neighboring districts are (from the north clockwise) Song, Nong Muang Khai, Mueang Phrae, Sung Men, Den Chai, and Wang Chin of Phrae province; Mae Tha and Mae Mo of Lampang province.

The Phi Pan Nam Mountains dominate the landscape of the district. Doi Pha Klong National Park is in Long district.

The district is divided into nine sub-districts (tambons), which are further subdivided into 89 villages (mubans). There are two townships (thesaban tambons), Ban Pin and Huai O, both covering parts of the same-named tambon. There are anotherer nine tambon administrative organizations (TAO).

No.	Name	Thai name	Villages	Pop.
1.	Huai O	ห้วยอ้อ	18	12,596
2.	Ban Pin	บ้านปิน	13	8,018
3.	Ta Pha Mok	ต้าผามอก	8	4,793
4.	Wiang Ta	เวียงต้า	10	6,874
5.	Pak Kang	ปากกาง	9	4,455
6.	Hua Thung	หัวทุ่ง	9	6,154
7.	Thung Laeng	ทุ่งแล้ง	12	7,539
8.	Bo Lek Long	บ่อเหล็กลอง	8	4,321
9.	Mae Pan	แม่ปาน	7	3,190

• amphoe.com (Thai)
• Doi Pha Klong National Park