Scientologist Louisa Hodkin took her fight to the Supreme Court after a High Court judge ruled that services run by Scientologists were not ''acts of worship''.
Five Supreme Court justices analysed the case at a hearing in London in July and ruled in her favour today, announcing that the Scientology church was a "place of meeting for religious worship".
Miss Hodkin wants to marry fiance Alessandro Calcioli in a Church of Scientology chapel in central London.
She took legal action after the registrar general of births, deaths and marriages refused to register the London Church Chapel for the solemnisation of marriages under the 1855 Places of Worship Registration Act - because it was not a place for ''religious worship''.
Supreme Court justices said religion should not be confined to faiths involving a "supreme deity".
They said the Church of Scientology held religious services, therefore its church was a "place of meeting for religious worship".
The justices unanimously allowed Miss Hodkin's appeal against the High Court ruling.
In 1970 the Church of Scientology launched a similar case.
Then the Court of Appeal ruled that Scientology did not involve religious worship because there was no "veneration of God or of a Supreme Being".
Miss Hodkin lost her High Court fight in December 2012 when Mr Justice Ouseley said he was bound by the 1970 Court of Appeal decision and therefore had to dismiss her challenge.
But he said Supreme Court justices should consider the question of whether Scientologists worshipped.
He said that because the Supreme Court was a more senior court than the Court of Appeal, Supreme Court justices might take a different view.
Miss Hodkin argued that the 1970 ruling should not be binding because Scientologist beliefs and services had evolved during the past four decades.
She said services were ''ones of religious worship'' and likened Scientology to Buddhism and Jainism.
Communities Secretary Eric Pickles had welcomed Mr Justice Ouseley's ruling.
Mr Pickles said the Church of Scientology might have been entitled to ''tax breaks'' - because of rules governing places of public worship - had a decision gone in its favour.
He said taxpayers would not want ''such a controversial organisation'' to get ''special'' treatment.