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.