Court in Nepal finds Lamichhane guilty of raping an 18-year-old woman at a Kathmandu hotel in 2022.
The judgement was announced after a repeatedly delayed trial that had left him free to continue his sporting career.
The 23-year-old has been the face of cricket in Nepal and was the only player from the country to take part in prominent Twenty20 leagues across the world.
He was suspended as Nepal’s captain last year and taken into custody after police issued an arrest warrant for him over the assault in 2022. He was later released on bail.
Lamichhane could face up to 10 years in jail. His lawyers said he would appeal the verdict to a higher court.
“We did not expect this judgement … we are frustrated,” lawyer Sabita Bhandari Baral told the Reuters news agency about Friday’s verdict by the Kathmandu District Court.
“We’ll definitely appeal,” she said.
District Court official Ramu Sharma confirmed the verdict to the AFP news agency.
“The event was not consensual,” he said.
The former captain’s on-field success has boosted the sport’s profile in the Himalayan nation over the past few years.
When authorities issued an arrest warrant, Lamichhane initially failed to return from Jamaica, where he was playing in the Caribbean Premier League.
He was dismissed as national captain and arrested last year, but Nepal lifted his playing ban after he was freed on bail.
This allowed him to remain in the national team, including for the World Cup qualifiers and September’s Asia Cup.
Lamichhane has consistently denied the charge against him and enjoyed strong public support despite the accusations.
Hundreds of cheering cricket fans welcomed him when he returned to the field in February.
But his continued playing career has also sparked anger and caused numerous Nepalis to disavow the team.
Scotland’s cricketers refused to shake hands with him after their matches during an international tournament in Dubai.
The case took more than a year to conclude after repeated delays on procedural grounds.
Cricket has been growing in popularity in Nepal and the country was given one-day international status by the world governing body in 2018.
Lamichhane has been a major part of this rise as the most sought-after Nepali cricketer in lucrative leagues around the world.
The leg spinner’s big break came when he was snapped up for the lucrative Indian Premier League, the world’s richest cricket tournament, in 2018.