PETA (People for the Ethical Treatment of Animals) has written an open letter to Most Revd Justin Welby urging him to ensure that exotic skins are not permitted on the catwalk.
The organisation said animals are slaughtered in brutal ways in the name of fashion and that this is "in no way compatible with the Church's message of kindness and compassion".
It's the first time any fashion house has displayed its collection at the historic church and some have criticised the decision.
Lambeth Palace and Westminister Abbey have not commented.
"Every exotic skin bag, shoe or jacket showcased by Gucci comes with a high price - and it's paid by animals who were mutilated and left to die slowly and in pain", said PETA Director Mimi Bekhechi.
"Slaughtering animals for vanity is in no way compatible with the Church's message of kindness and compassion."
PETA told Premier many of its Christian members had urged the organisation to speak out ahead of the show.
In the letter Senior Manager of Corporate Projects Yvonne Taylor says: "The miserable lives and violent deaths that these animals endure for the sake of expensive fashion are in direct opposition to God's message of kindness, mercy, charity and humility.
"Gucci's fashion show will without a doubt be the product of many acts of cruelty against God's creation. We urge you to follow the Pope's kind example of showing compassion towards animals by keeping cruelly produced exotic animal skins out of His holy church. "
Gucci declined to comment.
Listen to Premier's Antony Bushfield speaking to Yvonne Taylor:
