William Shortland, 42, was handed the sentence after a jury found him guilty of rape and other sexual offences against the victims when they were aged between 10 and 15 years old.
A jury at Leeds Crown Court heard how Shortland preyed on the victims over a period of five years before the offending came to light.
Shortland, of Barrowdale Crescent, Bramley, Leeds, continued to deny the offending at trial despite overwhelming evidence against him.
Mark McKone, prosecuting, told the court Shortland continued the abuse despite knowing the devastating psychological impact it was having upon the girls. The court heard both victims began to self harm during the offending.
On one occasion Shortland gave alcohol to one of the victims before carrying out the abuse. Shortland was found guilty of nine offences of rape and eight further sexual offences after a trial.
Michael Greenhalgh, mitigating, said Shortland continues to deny the offences. He said: “Mr Shortland appreciates I can say nothing about the offending behaviour itself in relation to him.” The barrister said it was accepted that he would be facing a long prison sentence after being found guilty of the offences.
He added: “He will have to come to terms with that over the course of the future years while he is incarcerated.”
Jailing Shortland, Recorder Simon Jackson, QC, said: “I am quite satisfied that this was a campaign of sexual crime committed by you.”
Describing the effect of his offending on one of the victims, Recorder Jackson said: “As a result of your conduct she felt crushed like an insect.
“I am quite satisfied, having read the victim personal statements, that there has been severe psychological harm to these young girls as a result of your appalling and vile conduct towards them. This was from first to last a wicked campaign of abuse.”
Shortland must also go on the sex offender register for life.