Greenfield is a village in the Saddleworth parish of the Metropolitan Borough of Oldham in Greater Manchester, England. It is east of Oldham, and east-northeast of the city of Manchester. It lies in a broad rural area amongst the South Pennines. To the east of the village Dovestone Reservoir, Chew Reservoir and Greenfield Reservoir lie within the Peak District National Park, though no part of the village itself lies within the Peak Park boundary.
Lying within the ancient county boundaries of the West Riding of Yorkshire, Greenfield is mainly situated on and around two roads in the Chew Valley in the Pennines. One of these roads is the main A635 road from Ashton-under-Lyne to Holmfirth.