The loosehead forward has spent the past four years at Ashton Gate, making 67 appearances for the Championship leaders.
But come the end of the season the 27-year-old will make the switch to the club who have been the main challenge to Bristol’s
promotion ambitions during this campaign.
“Jack O’Connell has been with the club for a number of years and he has remained professional and committed throughout his time here,” Bristol head coach
Pat Lam told the club’s website.
“We are grateful for the effort Jack has shown on and off the field and wish him well for the next chapter.”
Bristol hold top spot in the Championship standings after being defeated only once in 19 league matches so far this season, with Ealing 13 points adrift in second on 75 points.
O’Connell said of the deal: “It’s been a privilege to play for Bristol
Rugby for the past four seasons and to have built great friendships with my teammates.
“I’m looking forward to the future with Ealing, but I’d like to thank the club and the fans for the support they have shown me.”