Marian Heffernan (born 16 April 1982) is an Irish athlete who competed in the women's 4 ÃÂ 400 metres relay at the 2012 Summer Olympics. Heffernan is fifth in the all-time Irish record books for the women's 400 metres.
She is married to Irish Olympic race walker Rob Heffernan, with whom she has a son, Cathal, who is a footballer.