It comes after charges were withdrawn by the Crown Prosecution Service (CPS) at a hearing at Manchester Crown Court.
Mr Giggs, 48, denied assault and controlling or coercive behaviour towards Kate Greville, 38, and assaulting her sister Emma.
Judge Hilary Manley directed that he was not guilty on all three counts.
The retrial had been due to start at Manchester Crown Court on 31 July.
Jurors failed to reach verdicts following more than 20 hours of deliberations in his four-week trial in August last year.
He was not in court as the judge had agreed he need not attend.
His defence barrister, Chris Daw KC, said: “Mr Giggs is deeply relieved that the case has finally come to an end after almost three years of fighting to clear his name.
“He now intends to rebuild his life and career as an innocent man.”
The former footballer denied “losing control” and headbutting his ex-girlfriend and assaulting Ms Greville’s sister, Emma, 26, by elbowing her in the jaw during a row at his home in Worsley, Greater Manchester on 1 November 2020.
Mr Giggs was due to go on trial for a second time facing the same charges, after the jury in the first trial was discharged.
The jury was made up of 11 people – seven women and four men – after one of the original 12 jurors had fallen ill.
During the trial, Mr Giggs admitted to being unfaithful in relationships but, when asked if he had ever physically assaulted a woman, he said “no”, adding that he had never set out to control or coerce a woman.
The trial was told of the alleged assault on 1 November 2020 at his home in Worsley, Greater Manchester, where the couple returned following a row at dinner in which she accused Mr Giggs of messaging a string of women.
Jurors heard the pair tussled over their mobile phones, leading to Kate Greville’s sister Emma Greville, who was looking after the couple’s dog, calling the police.
Giving evidence, Emma Greville said her sister had screamed and fell to the floor and Mr Giggs told Emma Greville it was “her fault” and then threatened to do the same to her.
He denied the accusations and alleged Kate Greville kicked him in the head.
The former player made 963 appearances for Manchester United, scoring 168 goals.
