The Dutchman was signed by former boss Jim McIntyre in the summer of 2016 following a spell with NAC Breda.
The left-back departed Dingwall at the end of last season before performing a U-turn and agreeing a fresh 12-month deal at the start of the current campaign.
But he has now told new boss Owen Coyle he wants to leave - with permission granted following the deadline-day loan capture of West Brom teenager Max Melbourne.
In total Van der Weg turned out 59 times for the Staggies, netting two goals, with his final appearance coming during Sunday's 2-1 defeat to Rangers.
Ross County confirmed the news on Twitter, posting: "Defender Kenny van der Weg has left the club after his contract was cancelled by mutual consent (on Wednesday) night.
"We wish Kenny all the best in his future career."