Martin O'Neill, Roy Keane, Denis Irwin, John O'Shea, Brian Kerr and several members of the Cork City squad are in attendance, as are representatives for the Taoiseach and President Michael D Higgins.
Miller's former Republic team-mates Kevin Doyle and Aiden McGeady also attended.
Miller, who died last week at the age of 36, fulfilled his boyhood dreams by donning the soccer jersey during a career that gave great joy to many, mourners heard.
The world of football today came together to say goodbye to former Leeds United midfielder Liam Miller.
The ex-Celtic and Manchester United footballer was hailed as an "inspiration" at the Church of St John the Baptist in Ovens, Co. Liam wanted to survive for his family.
Former Republic player and manager Steve Staunton was another who attended the funeral mass.
Miller's battle with pancreatic cancer became known to the public in November, when he returned to Cork from America, where he had been coaching. "Our thoughts are with his family and friends at this time", the club tweeted.
Roy Keane and Martin O'Neill among mourners at Liam Miller's funeral after ex-Man United star lost cancer battle
Celtic players wore black armbands in Mr Miller's memory during their Scottish Cup victory over Partick Thistle on Saturday.
"Liam had a great career and has a reputation for being a quite lad who didn't seek out the attention and I hope he now gets the credit he deserves to plotting a route down a very hard road to emerge from an area of Cork where GAA dominates to play for some of the biggest teams in world football".
He joined Manchester United in 2004 and players donned black armbands in Sunday's 1-0 defeat to Newcastle United, while former manager Sir Alex Ferguson described Miller as "a good professional who served the club in an excellent manner".
"To turn out for his two favourite clubs in Celtic and Manchester United was an achievement few could match in Irish soccer in the last two decades and he lived the dream in every way possible by also playing for Cork City and on the worldwide stage for Ireland".
It was as a husband to Claire and a father of three that Liam Miller is best remembered among those who new him best.
He added: "Liam used his talents to the full and in so short a time".
He is survived by his wife Clare and his three children Kory, Leo and Belle.
Miller was buried in the cemetery adjoining the St John the Baptist Church. Cork, and City manager John Caulfield yesterday urged the people of Cork to "turn out in force" for the funeral.More news: German Social Democrats shake up leadership, focus on govt