Ruth M.J. Byrne, FTCD, MRIA, (born 1962) is an Irish cognitive scientist and author of several books on human reasoning.

She is the Professor of Cognitive Science, in the School of Psychology and Institute of Neuroscience, Trinity College Dublin.

Byrne was awarded a BA in Psychology from University College Dublin (UCD) in 1983.

She completed a PhD in Cognitive Psychology at Trinity College Dublin (TCD) in 1986.

[1] She was awarded the Royal Irish Academy's 2021 Gold Medal in the Social Sciences.