| Ysgol Gyfun Rhydywaun | |
| Motto: | Gwir. Gweithgar. Gwych. |
| Address: | Lawrence Avenue |
| County: | Rhondda Cynon Taff |
| Postcode: | CF44 9ES |
| Country: | Wales |
| Coordinates: | 51.7346°N -3.4932°W |
| Type: | Secondary |
| Established: | 1995 |
| Head Teacher: | Lisa Williams |
| Staff: | 80+ |
| Teaching Staff: | 60+ |
| Enrolment: | 1000+ |
| Gender: | Mixed |
| Lower Age: | 11 |
| Upper Age: | 18 |
| Houses: | 3 |
| Colours: | Red, Black and Gold |
| Medium Of Language: | Welsh |
Ysgol Gyfun Rhydywaun is a Welsh-medium comprehensive school in the Cynon Valley in the village of Penywaun, Rhondda Cynon Taf, Wales, to the northwest of the town of Aberdare.
The school was established on 1 September 1995 to deal with the increasing numbers of students attending five local Welsh-medium primary schools, who previously had to travel to secondary school in Pontypridd. It provides a Welsh-medium education for pupils from the Cynon Valley and from neighbouring Merthyr Tydfil County Borough, where there is no Welsh-medium secondary school.[1]
There are three houses, Welsh: Cynon, Dâr and Welsh: Taf, named after the local rivers, Cynon, Dare and Taff.