| Mynydd Llysiau | |
| Elevation M: | 663 |
| Prominence M: | 40 |
| Parent Peak: | Waun Fach |
| Listing: | Hewitt, Nuttall |
| Translation: | mountain of the fruit |
| Language: | Welsh |
| Location: | Black Mountains, South Wales |
| Grid Ref Uk: | SO215300 |
| Topo: | OS Landranger 161 |
Mynydd Llysiau is a subsidiary summit of Waun Fach in the Black Mountains in south-eastern Wales. It lies halfway between Waun Fach and Pen Allt-mawr. It is a distinguished summit with a steep eastern face. The summit, marked by a pile of stones, is long grassy ridge. To the south is Pen Twyn Glas, before which are two boundary stones that resemble grave stones.[1]