Geoff Eales (born 13 March 1951) is a Welsh jazz pianist, improviser and composer.
Eales was born in Aberbargoed, Wales. When he was eight years old, he learned 12-bar blues from his father, a pianist in a local dance bandt. In school he studied classical piano and French Horn, becoming a member of the Glamorgan Youth Orchestra and the National Youth Orchestra of Wales. He attended Cardiff University, receiving bachelor's, masters, and doctoral degrees. In 1980 he was awarded a Ph.D for his large scale orchestral work "An American Symphony" and a setting of Dylan Thomas' poem "In the Beginning" for tenor, French horn, and piano.
His thesis was entitled "Structure in the Symphonic Works of Aaron Copland".
After leaving school, he played piano on a Greek cruise ship and traveled around the world. For a few months he lived in New Orleans where he worked with Major Holley, Jimmy McPartland, Buddy Tate, and Earl Warren. He moved to London in 1977 and became a member of the Joe Loss band, then spent four years as pianist for the BBC Big Band. During the next fifteen years, he worked with Shirley Bassey, José Carreras, Rosemary Clooney, Jerry Goldsmith, Adelaide Hall, Jerry Goldsmith, Adelaide Hall, Henry Mancini, Lalo Schifrin, Kiri Te Kanawa, and Andrew Lloyd Webber. He released his debut album, Mountains of Fire in 1999. 
Eales has worked with singers and musicians from pop, rock, jazz, country, opera, and musical theater. He has played on soundtracks, TV shows, and jingles. He has been a featured soloist with symphony orchestras and has composed a symphony, a piano concerto, A Sussex Rhapsody, commissioned by the BBC Concert Orchestra, and chamber works.
- Mountains of Fire (Black Box, 1999)
- Red Letter Days (Black Box, 2001)
- Facing the Muse (Mainstem, 2002)
- Synergy (Basho, 2004)
- The Homecoming (33 Jazz, 2006)
- Jazz Piano Legends (2007)
- Epicentre (33, 2007)
- Master of the Game (Edition, 2009)
- Shifting Sands (33 Jazz, 2011)
- The Dancing Flute (Nimbus Alliance, 2013)
- Free Flow (33Xtreme, 2013)
- Invocation (Nimbus Alliance, 2014)
- Transience (Fuzzy Moon, 2016)