Rachel O'Reilly's mother Rose Callaly said that she and her family were very happy with the verdict.
However, Joe O'Reilly's mother, Ann O'Reilly, continued to maintain his innocence.
Speaking to reporters amid emotional scenes at the gates of the Four Courts complex, Ms Callaly said that Rachel had "got justice".
"I do not know what to say, I feel so overwhelmed. My daughter got justice today but we are so happy. We are so happy. It will not bring her back but thank God she has justice.
"We really mean it. Thank you from our hearts to everybody. I know it has not been easy on anybody but we got the right decision in the end and it has been worth it," she said.
Ms Callaly said that she wanted to thank everybody for their support.
She particularly highlighted the gardaí who she said had been "absolutely great to put such a case together". She also thanked the prosecution team.
"The police worked so hard, they have been absolutely brilliant throughout the whole thing and I can't thank them enough," she said.
Speaking of her daughter Rachel, she said: "She knows we love her and I wish she was with us in person. We will never forget you, Rachel. But you got justice today."
Ann O'Reilly left the court complex with other members of her family without commenting.
However, followed by reporters she was asked whether she believed that her son had committed the murder.
She replied: "I don't think he did it. I actually know he didn't do it."
Asked whether she had been the person who reported Rachel O'Reilly to social services over her alleged treatment of her children, she said that she had no comment to make.
Asked whether Joe O'Reilly would be launching an appeal, she said: "You will have to ask your friends in the Herald."
Supt Joe Kelly, the officer who led the investigation, told reporters outside the court that the gardaí were delighted with the verdict.
"We are particularly delighted for Rachel's family and all of her friends who have put up with an awful lot of difficulties over the last couple of years.
"On behalf of the Garda Síochána I would like to thank the people of north county Dublin and Dublin generally for all of their assistance over this time and I would like to thank all of my colleagues both retired and serving from the Louth/Meath division, Balbriggan district and also members from the National Bureau of Criminal Investigations who, without their professionalism and thoroughness, we would not be at this stage today."
