The Rural Municipality of Piney is a rural municipality (RM) in southeastern Manitoba, Canada, along the border with Minnesota in the United States.

According to Statistics Canada, the municipality has a land area of 2,433.77 km2.

It is bordered by the rural municipalities of Stuartburn, La Broquerie, and Reynolds, as well as the Buffalo Point 36 Indian reserve and an unorganized part of the province (Division No.

The municipality borders Roseau County in the U.S. state of Minnesota.

A minority but large part of Sandilands Provincial Forest is located here, as is a small part of Northwest Angle Provincial Forest.