Stephen Lawrence's father Neville has called on the two men imprisoned for his son's murder to turn in the other people involved in the racist attack.
Mr Lawrence said the sentencing of Gary Dobson and David Norris was "only one step in a long, long journey" and called for the other killers to be brought to justice as well.
Addressing reporters outside the Old Bailey, he said: "One of my greatest hopes is that these people have now realised that they have been found out.. and they are going to give up the rest of the people so that I (can) come out here again in a year's time and talk to you people again."
Stephen's mother, Doreen, said it had been a "really difficult day" but added that she could now start moving on with her life. She thanked the judge, accepting that he was unable to pass stiffer sentences on Dobson and Norris.
"The sentences that happened may be quite low, but at the same time the judge's hands were tied. And for that, as much as he can do, I am very grateful," Mrs Lawrence said outside court.
Meanwhile, London mayor Boris Johnson welcomed the sentencing but added: "The failures in the Stephen Lawrence murder case have been a long-running sore for us as a city and an embarrassment to our police force. I, like everyone across the country, have always been in awe of the Lawrence family's dignified pursuit of justice. They are a fine example to us all.
"Today's sentencing is a reflection of their tireless determination and also sends a bold message to anyone else involved in this crime. This case is certainly not closed but I am relieved that some justice at last has been done."
Deborah Glass, of the Independent Police Complaints Commission, said the initial investigation into the murder was "truly shocking". But she said Scotland Yard now deserved credit for the two prosecutions.
"It is important to acknowledge the changes that have been made over the past decade, but there is equally no doubt that much remains to be done to increase the confidence of black and minority ethnic communities in policing," Ms Glass added.
US civil rights campaigner Reverend Jesse Jackson said the length of the prison sentences "cheapens black life". On a visit to the Occupy movement outside St Paul's Cathedral, he added that "justice delayed is justice denied".