The opener was fuming when given out against Australia in the thumping win on Friday.
Roy was given out by umpire Kumar Dharmasena for 85 but replays showed the England star got nowhere near the ball.
Dharmasena took an age to raise his finger prompting Roy to ask for a review.
But the World Cup finalists had already lost it through Jonny Bairstow earlier in the innings.
Roy couldn’t believe it and thought the ball should have been signalled a wide.
But instead the explosive opener was given out with Pat Cummins picking up a valuable wicket for Australia.
Television broadcasters showing the match had to apologise for the aftermath which saw Roy swear in anger at the umpires.
And eventually the Surrey batsman was told to leave the field by square leg umpire Marais Erasmus.
The ICC found Roy guilt of dissent and fined him 30 per cent of his match fee but he will be available for the final.
A statement read: “England batsman Jason Roy has been fined for breaching Level One of the ICC Code of Conduct during England’s eight-wicket win over Australia on Thursday.
Roy top-scored with 85 in England’s chase of 224, helping the tournament hosts to their first Men’s Cricket World Cup final in 27 years.
“However, the right-hander was found guilty of breaching Article 2.8 of the ICC Code of Conduct for Players and Player Support Personnel after showing dissent to the umpire upon his dismissal in the 19th over of the innings.
“Roy has been fined 30% of the match fee after admitting the offence and sanction, with no formal hearing to take place.
“Two demerit points have been added to his disciplinary record. He won’t face any suspension.”
England romped home at Edgbaston against their arch-rivals Australia winning by eight wickets after bowling their opponents out for just 223.
After the match Joe Root was ecstatic with the performance of his team-mates and cannot wait to take on New Zealand.
He said: “I’m still pinching myself. It’s an amazing feeling – from the second ball of the day we put Australia under a lot of pressure. We bowled exceptionally well in those first 10 overs and then we were clinical with the bat.
“That 100 partnership to start things off is irreplaceable – when those two boys play in that manner, it makes it very difficult for any side.
“You don’t get these opportunities very often. Naturally there are some nerves but there would be in their dressing room as well.
“You try and strip it back to executing your lengths and making it difficult for them – if they take risks then you are in the game.
“The way Woakes and Archer have played in the last three games with the new ball has been outstanding. To create chances and to restrict them to under 30 in two of the last three games has been phenomenal.”
England take on New Zealand in the Cricket World Cup final on Sunday from 10.30am UK time at Lord’s.
Express Sport will bring you ball-by-ball coverage of the showpiece event as Eoin Morgan’s side look to make history.