Fionnuala McCormack (née Britton; born 24 September 1984 in Wicklow) is an Irish runner who has competed at a range of distance running events.

She was fourteenth in the senior race at the 2007 IAAF World Cross Country Championships – the second best European performer behind Jessica Augusto (12th).

[1] She just missed out on a medal at the 2010 European Cross Country Championships, finishing with the same time as bronze medallist Ana Dulce Félix.

[13] On 3 March 2013, she won a bronze medal in the 3000 metres final at the 2013 European Athletics Indoor Championships in Gothenburg.

[17] Her first success under her married name was a team bronze at the 2015 European Cross Country Championships, where she narrowly missed an individual medal in fourth place behind Karoline Bjerkeli Grøvdal.

In 2019, she competed in the senior women's race at the 2019 IAAF World Cross Country Championships held in Aarhus, Denmark.