Gruffudd Maredudd Bowen Rhys (Welsh pronunciation: [ˈɡrɨ̞fɨ̞ð maˈrɛdɨ̞ð ˈbowɛn ˈr̥ɨːs]; born 18 July 1970) is a Welsh musician, composer, producer, filmmaker and author. He performs solo and with several bands, including Super Furry Animals, which obtained mainstream success in the 1990s. He formed the electro-pop outfit Neon Neon with Boom Bip. Their album Stainless Style was nominated for the 2008 Nationwide Mercury Prize. He won the 2011 Welsh Music Prize for his album Hotel Shampoo, which was followed up by American Interior in 2014, accompanied by a film, a book and a mobile app. His most recent album, Dim Probs, was released in 2025. He is considered a figurehead of the era known as Cool Cymru.

Rhys was born 18 July 1970 in Haverfordwest, Wales. He has a brother and a sister; his father was Ioan Bowen Rees (13 January 1929 – 4 May 1999), a "poet, essayist, polemicist, mountaineer, internationalist ... and a White Robe Druid of the Gorsedd of Bards". Bowen Rees "campaigned all his life for Welsh rights, language and culture" although he did not believe in the narrow view of nationalism, glorifying one country over another, rather that the "battle for Wales is the battle for all small nations, all small communities, all individuals in the age of genocide". Rhys's mother, Margaret Wynn Meredith, shared his father's love of writing and was a poet.

Rhys was educated at Ysgol Dyffryn Ogwen, Bethesda, Gwynedd, North Wales and was awarded a degree in art at Manchester Metropolitan University.

As a teenager in 1985, Gruff Rhys played drums for the North Wales band, Machlud, appearing at the Pesda Roc festival in Bethesda. After playing drums for the band Emily, Rhys found fame in Wales as the front man of Ffa Coffi Pawb. Translated, the name means 'everyone's coffee beans', though if said quickly in Welsh, it can sound like 'fuck off everyone' in English and Welsh combined.

On signing to Ankstmusik, Ffa Coffi Pawb became one of the leading bands on the Welsh music scene during the Cool Cymru movement, and released three albums – Clymhalio, Dalec Peilon and Hei Vidal!.

Rhys plays the guitar in an unusual style. Although he is right-handed, he learned to play left-handed on his brother's left-handed guitar. Once his brother left home, Rhys only had access to a right-handed guitar. As he had already learned to play left-handed, and rather than invert the nut and re-string it, he taught himself to play the right-handed guitar upside down so the bass strings are on the bottom. Today, Rhys still plays left-handed on an upside down right-handed guitar.

When Ffa Coffi Pawb disbanded in 1993, Rhys and drummer Dafydd Ieuan, of Rhoscefnhir, Anglesey, who had played for Catatonia, Anhrefn, Hanner Pei and many other Welsh language bands, formed the basis of Super Furry Animals. They soon settled on a line-up consisting of Rhys on vocals and guitar, Ieuan on drums, his brother Cian Ciaran (formerly of WWZZ) on keyboards, Huw Bunford (formerly of U-Thant) on guitar and Guto Pryce on bass. This line-up has remained constant to the present day, although the role of each member has become more flexible, particularly in the studio.

In 1995, following a couple of largely Welsh-language EPs on the Ankst label, they signed to Creation Records. Apparently, when offering them the deal after a gig, Alan McGee, head of Creation, asked that they sing more songs in English. Rhys pointed out that all the songs that night had been in English. Super Furry Animals went on to release their critically acclaimed first album, Fuzzy Logic, in 1996 – the first time Rhys had recorded in English. He later observed that his singing sounded like a random collection of accents – but it was nevertheless very successful.