Osolase, who has HIV, showed no emotion as sentence was passed.
Judge Williams told him he put his victims "in fear" by using juju rituals to force their obedience and secure their silence.
She said he was responsible for a "cruel deception" by promising the girls, one of whom lived under a bridge in Nigeria, a better standard of life in the UK.
The judge said: "You were dealing in exploitation and manipulation and degradation. You have been convicted on clear and compelling evidence."
She went on: "I have seen and heard you give evidence and you are undoubtedly a very, very dishonest man. You are arrogant and manipulative, you are devoid of conscience, devoid of any compassion to your victims."
The judge said Osolase treated the girls as "objects" to be sold as "sex slaves". And she said the fact that he raped one girl knowing he has HIV was a "seriously aggravating" feature.
It was recommended that Osolase be deported once he has served his sentence.
Detectives revealed that one 16-year-old girl described how a juju ceremony performed on her in Nigeria involved her having samples of blood extracted.
Hair from her head and intimate parts were also cut and she was made to swear an oath of silence and smuggled into Britain before an unsuccessful attempt was made to farm her out to Italy.
Witchcraft rituals are sometimes used by Nigerian traffickers to force victims into obedience or compel them to pay back vast sums of money.
A senior detective said Osolase corrupted the well-established belief of juju in an attempt to "gain control and bend the wills" of his young victims.
During the six-week trial, Osolase, nicknamed "Uncle", refused to admit trafficking the teenagers, forcing them to relive the crimes in front of a jury.
Some of the girls had travelled to Britain with dreams of gaining modelling work or a better education, but prosecutors said they instead endured "heartless abuse" at every turn.
Police believe there were at least 25 suspected victims of the trafficking ring, which smuggled girls using fake passports and visas from Nigeria and into the UK and on to countries including Italy and Spain.
Investigators said the case was difficult to bring to court because human trafficking victims often fear retribution against themselves and their families back home.
Their experience of authorities in their home country often leaves them lacking confidence in the justice system but British officials said the girls were courageous in giving evidence.
Painstaking inquiries were conducted on a mass of data from pre-paid credit cards, email addresses, flight records and mobile phones to prove Osolase was involved in smuggling the girls to Britain.
He was stopped at Stansted Airport in Essex in April last year, leading inquiries by the UK Border Agency to then be passed to the Kent and Essex Serious Crime Directorate.
Investigations revealed that he was the prime suspect in multiple human trafficking offences where girls had been flown from Nigeria to the UK before being sent out to Europe.
In mitigation, Anthony Orchard QC, defending, said Osolase suffers from glaucoma, rendering him 90% blind in one eye.
He also said Osolase disclosed that he had HIV voluntarily to police, and that his German wife has stood by him throughout the trial process.
Mr Orchard said: "Mr Osolase acknowledges and regrets the consequences of his actions in relation to taking the girls out of the UK, and he has to bear the consequences of those actions."
Experts said juju is such a strong spiritual belief that Osolase's victims will still believe they are tied to their contract with those who forced them to swear an oath.
Detective Inspector Eddie Fox, from the Kent and Essex Serious Crime Directorate, said: "Osolase is an evil, dishonest and manipulative man who bent the will of his victims and subjected them to a horrendous ordeal.
"The length of the sentence reflects the terrible nature of his crimes and I feel that justice has been served.
"The investigation was both challenging and complex and we are grateful to our partner agencies and the CPS for their efforts in bringing Osolase to justice.
"Most importantly this trial gave the girls the opportunity to tell their story and let their voices be heard. They have spoken on behalf of the other women and girls who have not been located.
"All three of Osolase's victims showed great bravery in coming forward. Their courage has prevented other girls from having to suffer a life of misery."
Colin Walker, deputy director of UK children rights organisation Ecpat UK, said: "We welcome the dedication of police in bringing this case to court and shining a light on the horror and reality of child trafficking in the UK today.
"These children were subject to terror, abuse and will live with the scars of what he did to them for the rest of their lives.
"We pay tribute to the bravery shown by these three girls who demonstrated such tremendous courage to stand up to their abuser and to tell the world what he did in order to stop it happening to other children.
"Theirs is a message that needs to be heard and needs to be taken seriously.
"Child trafficking is here in the UK and cannot be ignored.
"Last year the Government identified nearly 500 children and more than 2,000 adults trafficked to the UK, yet there were only eight convictions under human trafficking legislation.
"These are shamefully low rates of conviction. More must be done to bring these criminals to justice and prevent more vulnerable children falling victim to abuse."
Juju expert and former Metropolitan Police detective Andy Desmond, who delivers training with Ecpat UK on juju and witchcraft, said: "Juju is such a powerful spiritual belief that has been hijacked by the traffickers to control their victims.
"Although this court case is over and the trafficker has been sent to jail, the victims will strongly believe that they are still tied to their contract with the demi-gods who they were forced to swear an oath to.
"For them, it will take many years to recover or feel safe from the juju."