The jail sentence of Vickrum Digwa, who was convicted of the murder of Henry Nowak, has been referred to the Court of Appeal by the solicitor general under the Unduly Lenient Sentence scheme.
Digwa, 23, was jailed for life and given a minimum term of 21 years by Judge William Mousley KC at Southampton Crown Court on 1 June.
Solicitor General Ellie Reeves KC MP said she hoped the referral would help to bring justice to Nowak's family.
The 18-year-old student was repeatedly stabbed in the street with a 21cm (8in) blade which Digwa claimed he was carrying because of his Sikh faith.
Nowak was initially arrested and handcuffed by police during the incident on 3 December, before officers realised he was severely injured.
Digwa falsely told police on the scene that Nowak had attacked and racially abused him.
In police body-worn video, the student, from Chafford Hundred in Essex, repeatedly told officers that he had been stabbed and could not breathe.
The footage, which was released following the sentencing hearing, led to violent protests in Southampton on 2 June.
In a statement, Reeves said: "This case horrified me, and I know that feeling is shared by the British public.
"It is right that difficult questions need to be answered about the way the police handled Henry's Nowak's murder, while my role is to review Digwa's sentence for his crimes.
"No sentence can ever undo the devastation that Henry's family have suffered, or fill the void left by his loss.
"But I hope this referral goes some way towards bringing them the justice they deserve."
Prime Minister Sir Keir Starmer, who previously described it as an "awful, shocking case", met members of the Nowak family at Downing Street on 4 June.
Afterwards, Sir Keir said he had been "profoundly humbled" by the meeting and that Nowak deserved "a legacy that goes beyond this awful tragedy".
So far, 23 people have been charged over the protests on 2 June and 13 defendants have been jailed.
The Sikh Federation has called on the government to set up an inquiry into issues in the case, citing the carrying of blades and anger directed towards member of the Sikh community since the murder.
Hampshire and Isle of Wight Constabulary is being investigated by the Independent Office for Police Conduct over the case.
An inquest into Henry Nowak's death is due to be held in Winchester in September 2027.
