The actor, who played Ron Weasley in the Harry Potter movies, failed in his latest attempt to get a £1m tax refund he believes is owed from the Revenue.
In 2016, Grint tried to claim the tax back by using a change in accounting dates to avoid paying a higher tax rate on his earnings.
At the time Judge Barbara Mosadele found Grint had changed his accounting date so 20 months of income would be taxed in 2009/10, one year before the top tax rate rose from 40%to 50%.
Because HMRC prevented him from doing so, Grint had to make an additional tax payment of £1m.
The judge ruled at the time that he was not entitled to the refund as he had failed to give a valid reason for such change, but he took his case to the Upper Tribunal.
Last week, Justice Rose and Judge Richards dismissed his latest appeal, ruling that the actor had failed to meet the conditions on which the law would recognise a valid change in accounting dates.
An HMRC spokesperson said, "HMRC welcomes the Upper Tribunal’s decision in this case which agreed with our interpretation of the facts and law."