Roger Llewelyn Davies (born 13 January 1954) is a British astronomer and cosmologist, one of the so-called Seven Samurai collaboration who discovered an apparent concentration of mass in the Universe called the Great Attractor.

He has pioneered the use of a new class of astronomical spectrograph to measure the masses and ages of galaxies, as well as search for black holes in their nuclei.

As a teenager Davies also attended evening classes run by the Workers' Educational Association, becoming a lifelong supporter of astronomy outreach work.

He became Head of Astronomy at Durham University in 1994 where he developed his interest in integral field spectroscopy and played a leading role in building instruments for Gemini (GMOS)[3] and the William Herschel Telescope (SAURON).

As President of the Royal Astronomical Society between 2010 and 2012,[6] Davies worked with the RAS community to make the continued case for astronomy and geophysics, an area in which the UK excels.