Everton star Coleman suffered the horrific injury during Ireland’s 0-0 draw with Wales last night.
Wales’ Neil Taylor was sent off for the challenge that left Coleman needing oxygen from the medical staff.
He was immediately taken to hospital and was found to have a double break in his tibia.
The 28-year-old, who was captaining his country last night, was rushed to hospital in Dublin.
Speaking after the game, Ireland manager Martin O’Neill said: “Seamus has gone to hospital, it’s been confirmed by a doctor that he has broken his leg,” added O’Neill.
“Obviously, it’s a real blow to him. He’s having the season of a lifetime at club level. He’s a big player for us, a great captain and a great character.
“It’s a big loss to Everton, a big loss to us. But he’ll fight back I hope. It puts things in perspective.”
Coleman is expected to be out for the remainder of Everton’s Premier League campaign.
The Toffees sit seven in the table as they mount a late push for a top-four finish.
Coleman has played 33 games for club and country this season, scoring five goals.