Geraldine Byrne Nason (born 1959) is an Irish diplomat who is currently Ambassador of Ireland to the United States of America.

[2] Nason served as Second Secretary General of the Department of the Taoiseach from 2011 until 2014, making her the highest-ranking female civil servant in the country.

[2][4] In summer 2014, she produced a report of issues that might affect Ireland if the United Kingdom left the European Union.

[2] Alongside her Swedish counterpart, she started an informal network of women ambassadors and journalists in Paris.

[6] In August 2017, Nason was appointed as Ireland's permanent representative to the UN in New York by Taoiseach Leo Varadkar, replacing David Donoghue.