Moel Sych (pronounced [mɔi̯l sɨːχ]) with a height of 826.7 metres (2,712 ft) is a subsidiary summit of Cadair Berwyn in north east Wales.

[3] The summit lies at the triple historic county boundary point of Montgomeryshire, Denbighshire and Merionethshire.

It is the highest point (historic county top) of Montgomeryshire.

The summit was often considered to be the highest summit in the Berwyns (and therefore the county top of Denbighshire as well as Montgomeryshire) until the Cadair Berwyn North Top, then known as Cadair Berwyn was found to be of the same height.

The summit has a cairn, and overlooks Llyn Lluncaws in the southern Cwm.