New website JustPray.uk, which is run by the Church of England, had wanted to show a 60 second advert of The Lord's Prayer before the film across England.
Odeon, Cineworld and Vue, which control 80% of cinema screens around the country, have refused to show the advert because they believe it "carries the risk of upsetting, or offending, audiences".
Fisher, who stars as Princess Leia Organa in the film told the Mail on Sunday she had "no idea" why it would be rejected.
"Offended? No. People should get a life. I don't think it is offensive to have a 'power of prayer' advert before Star Wars," she said.
"I have never seen an advertisement like this, but if the theatre is like a hotel room, then they have every right to put up a power of prayer advert.
"It's advertising, so it has to be advertisers that are objecting.
The Church branded the decision "plain silly" and said it had a "chilling effect" on free speech and is considering taking legal action under the Equality Act which bans commercial organisations from refusing services on religious grounds.
Christians from many walks of life, including a weight lifter, a police officer, a commuter, refugees in a support centre, school children, a mourner at a graveside, a festival goer and the Archbishop of Canterbury, are all shown in the advert.