Summer Leys is a local nature reserve at Wollaston in the Upper Nene Valley, in Northamptonshire, England.

[1][2] The reserve, created from former gravel pits, covers just under 50 hectares (120 acres) and is primarily wetland, with some grassland and woodland habitats, and hedges.

[2] The grassland is managed by the use of grazing cattle and rare-breed sheep, supported by a grant from the SITA Trust.

[3] The northern perimeter of the reserve is delineated[2] by the trackbed of the former Northampton and Peterborough Railway, closed in 1972.

[5] The reserve and neighbouring gravel pits, collectively the Upper Nene Valley Gravel Pits, are designated as a Site of Special Scientific Interest (SSSI), a Special Protection Area (SPA) and a Ramsar wetland of international importance due to their importance for wintering wildfowl.