Three police officers were found guilty of destroying evidence and sentenced to five years in prison.
The victim, who belonged to a Muslim nomadic tribe, was found in a forest near Kathua city in January 2018.
The case sparked widespread anger and made headlines when Hindu right-wing groups protested over the men's arrest.
Eight people, including a former government official, four policemen and a minor, were charged in connection with the crime. One of them has been acquitted and the minor is set to be tried separately.
All of them had pleaded not guilty to the charges against them.
The case became one among many high-profile ones that prompted India to pass a new law which introduced death penalty for anyone convicted of raping a child under 12.
But it is still left to the judge's discretion to decide whether or not to hand out a death sentence.
The eight-year-old girl went missing in the new year of 2018 and her battered body was discovered almost three weeks later.
According to investigators, the child was confined to a local temple for several days and given sedatives that kept her unconscious. The charge sheet alleged that she was "raped for days, tortured and then finally murdered".
They added that the child was targeted because the men wished to terrorise the tribe - known as Gujjars - into leaving.
A child is sexually abused every 15 minutes in India, according to government crime figures up to 2016, and there has been a steady rise in offences against children.
The BBC's Geeta Pandey in Delhi says India is home to the largest number of sexually abused children in the world, but there is a reluctance to talk about the topic so the real number of cases could be much higher.
Who are the convicted men?
Seven men were tried in a specially convened fast-track court on Monday and six were found guilty.
Investigators said that Sanjhi Ram, a 60-year-old retired government officer, allegedly planned the crime with the help of police officers Surinder Verma, Anand Dutta, Tilak Raj and Deepak Khajuria.
Ram's son, Vishal, his nephew, a juvenile, and his friend, Parvesh Kumar, were also accused over the rape and murder.
While Vishal was acquitted, Ram, Khajuria and Kumar have been sentenced for life. The remaining three have been handed five-year sentences.
After the verdict, the lawyer representing the child's family told BBC Punjabi that it was a "victory of constitutional spirit". He added that "the whole country fought this case, irrespective of religious affiliations".
The lawyer representing the accused said that despite the conviction, the case was based on "circumstantial evidence" and has pleaded for minimum punishment for the six men. He added that there were mitigating circumstances, including the fact that the men were the sole breadwinners in their families.