"The defendant used his position of power over the victim to gratuitously inflict violence upon him over a long period of time," John McFarlane, the Scotland Yard detective who led the investigation, said after the verdict.
"After the victim's body was discovered he made every effort to evade justice, including misleading police by alleging that the victim had been robbed and then trying to claim diplomatic immunity, which he was not entitled to in the UK."
Saud was fuelled by champagne and cocktails when he murdered the 32-year-old in a ferocious attack after the pair had returned from a Valentine's Day night out, the two-week trial heard.
The victim, also a Saudi, was left with severe injuries including bite marks on both cheeks which prosecutors said showed a clear "sexual element" to the killing.
Saud -- whose lawyers argued that he could face the death penalty in Saudi Arabia over the revelations of homosexuality aired at the trial -- showed no emotion as the verdict was read out.
The prince had denied murder and a second charge of grievous bodily harm with intent in relation to an earlier alleged assault in a hotel lift that was captured on CCTV footage. He had admitted manslaughter.
The trial heard that the two men had stayed together at London's Landmark Hotel for nearly a month as part of an "extended holiday" that had also taken them to Italy, Hungary, the Czech Republic and Morocco.
Saud had claimed the pair were friends and that he was heterosexual, but the court heard the prince had ordered gay escorts in London and had frequently looked at websites for gay massage parlours and escort agencies.
Prosecutors said he repeatedly assaulted Abdulaziz and that two brutal attacks were captured on CCTV by the hotel lift. The victim was so worn down by the violence that he let Saud kill him without a fight, they said.
Witnesses had told the court that Bandar -- an orphan who was adopted into the family of a low-ranking civil servant in Jeddah -- was treated "like a slave".
After the killing, the prince spent hours on the phone to an unidentified contact in Saudi Arabia before finally calling his chauffeur to the room, at which point the body was discovered on a bloodstained hotel bed.
Police said he had dragged the body from the bathroom to the hallway and then the bedroom "in an attempt to cover his tracks".
A post-mortem found that Abdulaziz had suffered chipped teeth, heavy blows to the head, injuries to the brain and ears and severe neck injuries consistent with strangulation by hand, the trial heard.
The prince's father, a nephew of King Abdullah, was in court for the verdict.