Bruno Gallo, 70, was found guilty of having sex with the minors, aged between 16 and 17 years old, by a judge in West Nusa Tenggara province on Wednesday.
The Italian, who has lived on the island for 20 years, is accused of luring the victims to his house with money and gifts, where they agreed to have sex with him.
Although consensual sex between gay couples is allowed in most Indonesian provinces, the age of consent is 18.
"He was sentenced to five years because we have underaged victims. What he committed violated the children's protection law," Didiek Jatmiko, spokesman for Mataram district court, told AFP.
Gallo's lawyer Denny Nur Indra said his client would not file an appeal but claimed he did not know his actions were illegal.
"He admitted that he has a sexual disorder, he likes same-sex children, but he should have been treated," Indra said.
Lombok and several other Indonesian islands, including Bali, have reputations as havens for foreign paedophiles and child sex networks.
Last year 70-year-old Australian paedophile Robert Andrew Fiddes Ellis was sentenced to 15 years in prison after a court found him found guilty of abusing 11 girls at his home in Bali.
Gallo was ordered to pay a 100 million rupiah ($7,500) fine or serve an additional three months in prison.