President Michael D Higgins has led congratulations in Ireland following the election of the new Pope Leo XIV.
Mr Higgins said Cardinal Robert Prevost, an American, becoming Pope was "an immensely significant moment for all those of faith".
Mr Higgins said: "This is an immensely significant moment for all those of faith and goodwill around the world who look to the papacy for spiritual guidance, moral clarity and global leadership at a time described by his predecessor Pope Francis as needing the vocation of diplomacy.
"Pope Leo XIV assumes this important role at a time of great challenges for the world.
"I send Pope Leo my very best wishes as he begins his pontificate, and I welcome his statement that he is prepared to lead with compassion, wisdom and an enduring commitment to the values of peace, justice and human dignity."
The Taoiseach Micheál Martin said: "The scenes of great joy and celebrations in St Peter's Square are a reflection of the hopes and goodwill felt by people of the Catholic faith from all around the world towards the new Pope.
"I hope that this groundswell of best wishes towards Pope Leo XIV will give him strength and support as he takes on the immense responsibility of his pontificate.
"I know that he has the best wishes of all Irish people, of all traditions," added Mr Martin.
Archbishop Eamon Martin also welcomed the appointment of Pope Leo XIV.
In a statement, he said: "Pope Leo is a missionary at heart with a breadth of international experience and background - having ministered in three continents.
"His opening words about peace and 'building bridges' indicate that he wishes to work for reconciliation and unity in the Church and in the world.
"His choice of name suggests that a commitment to Catholic social teaching will be a hallmark of his papacy," said Dr Martin.