Diamond is an unincorporated community in Harney County, Oregon, United States. Diamond is located west of Oregon Route 205 and south of Malheur Lake, 52 miles (84 km) south-southeast of Burns by highway. Its post office is assigned ZIP code 97722.
Settled in 1874–75, the community got its name from a diamond-shaped branding iron used by a local cattle rancher.
According to the Köppen Climate Classification system, Diamond has a semi-arid climate, abbreviated "BSk" on climate maps.