The Cambrian Mountains (Welsh:'Mynyddoedd Cambria', in a narrower sense: Elenydd) are a series of mountain ranges in Wales.

Originally the term "Cambrian Mountains" was applied in a general sense to most of upland Wales. Since the 1950s, its application has become increasingly localised to the geographically homogeneous Mid Wales uplands, known in Welsh as the Elenydd, which extend from Pumlumon to Mynydd Mallaen. This barren and sparsely populated 'wilderness' is often referred to as the Desert of Wales. The area includes the sources of the River Severn and River Wye, and was unsuccessfully proposed as a National Park in the 1960s and 1970s. The highest point of the range is Plynlimon, at 2,467 feet (752 m).