President Michael D Higgins has hailed the strength of the country's film industry on a night when home-grown talent was strongly represented at the Oscars.
Brooklyn star Saoirse Ronan, 21, missed out to Brie Larson in the best actress category but showed her roots in her dress choice.
"I wore green at my first Oscars as well. I wanted to wear green because I'm very proud to be Irish and Calvin Klein made this for me," she said.
Other Irish nominees included Steve Jobs star Michael Fassbender, who was pipped to the best actor Oscar by The Revenant's Leonardo DiCaprio, and Lenny Abrahamson, who was nominated for best director for Room.
The Revenant director Alejandro Inarritu won that gong but Larson's best actress Oscar was for her role in Abrahamson's film.
And the Irish did not go home empty handed as director Benjamin Cleary's movie Stutterer won the Oscar for best live action short film.
In his acceptance speech Dubliner Cleary said: "You know, when you make your first ever film, you've got to convince a lot of people to jump on board and take a risk with a first-time director, and, you know, to every single member of the cast and crew of Stutterer for jumping on board and taking that risk with me, I'm forever grateful.
"And to the Academy for this award. It's such a huge honour. Thank you so much.
"To my amazing parents for all the support, thank you."
Cleary also paid tribute to the stars of the film, about a man with a crippling stutter and his online relationship with a woman.
"Chloe Pirrie, you're amazing, wherever you are up there.
"Matthew - to the wonderful Matthew Needham, you are this film, brother, thank you so much."
Cleary finished by declaring: " Every day is a proud day to be Irish, but today even more so than usual. To everyone for all the support back home, thank you so much."
Speaking on the red carpet, Ronan said attending the Academy Awards was "surreal".
And she paid homage to the other actresses nominated in her category, including Carol star Cate Blanchett and 45 Years star Charlotte Rampling.
She said: "You've got people like Cate as well, and Charlotte, who have been in the game for such a long time, and have such an incredible body of work.
"To be put in the category with them for anything is wonderful."
President Higgins has said the strong line-up of Irish actors and film-makers was a "tribute to the Irish film industry".
Mr Higgins said: " It is now accepted internationally that Ireland has an accomplished film industry, providing a great return from the investment in film - made over recent decades - through highly skilled jobs and an enhanced international reputation."