| Lucumayo | |
| Name Etymology: | Quechua |
| Subdivision Type1: | Country |
| Subdivision Name1: | Peru |
| Subdivision Type3: | Region |
| Subdivision Name3: | Cusco Region |
| Source1 Location: | Huayopata District |
| Source1 Coordinates: | -13.1419°N -72.3083°W |
| Mouth: | Vilcanota River |
| Mouth Location: | Huayopata, Maranura and Santa Teresa Districts |
| Mouth Coordinates: | -13.004°N -72.6248°W |
| Tributaries Left: | Tunkimayu |
The Lucumayo (possibly from Quechua luq'u old hat that has lost ist form; hollow, depression (of an area), mayu river) is a river in Peru located in the Cusco Region, La Convención Province, Huayopata District. Its waters flow to the Urubamba River.
Lucumayo river originates in the Urubamba mountain range near mount Veronica. It crosses the district from southeast to northwest along the villages of Chachayoc, Alfamayo, Lucumayo, Huacarumiyoc, Huamanpata, Incatambo, Sarasarayoc, Huamanmarca and Huyro. Some of its numerous little affluents from the right are Alfamayo, Chaquimayo, Incatambo and Sirinayoc. Its main tributary is the Huamanmarca. The village of Wamanmarka lies near the confluence of these rivers, on the right bank of the Luq'umayu. This is where the archaeological site of Huamanmarca is situated. The Tunkimayo is one of the left tributaries.
East of Wamanmarka the river turns to the west and keeps this direction up to the confluence with the Vilcanota River as a right affluent. It is east of Pampayoc on the border of the districts of Huayopata, Maranura and Santa Teresa.