President Michael D Higgins has added his voice to those congratulating Barack Obama.
He has assured him of the "continued goodwill and best wishes of the people of Ireland".
In a statement, President Higgins said: "The international community is facing many daunting challenges and we look forward to your continued leadership."
He said the relationship between Ireland and the US has prospered during Mr Obama's first term, and Mr Higgins is confident relations will be further advanced during the next four years.