Spending cuts mean Latin and Classics are under threat at High Storrs school in Ecclesall.
Some of its former pupils have now lent their support to the fundraising campaign, which if successful, would ensure the subject would continue to be taught at the school for the next decade.
Businessmen Sir Andrew Cook and John Hancock, who were both taught Latin at High Storrs in the 1960s, are among the school's most notable alumni.
Last night, they both said they would pledge money to protect the subject which Sir Andrew described as 'a buttress against barbarism'.
Sir Andrew, chairman of the Sheffield-based industrial group, William Cook, said: “I was dismayed to learn that Latin teaching was at risk. It is a backbone of civilisation and learning.”
He said he regretted the tendency towards 'fashionable' subjects such as Media Studies in today’s curriculum.
“Any subject with the word studies in the title is a quasi subject rather than a real one,” he said.
Mr Hancock, a past chairman of the British American Business Council, who now lives in the US, added: “Knowledge of Latin disciplines the mind and helps one understand many things.”
The former grammar school offers five languages including Urdu, but Head of Classics, Gina Johnson, said the school's Latin provision for GCSE pupils was under threat.
“The school is delighted to have us here because we’re a unique selling point – but the sticking point is money,” she said.
She conceived the crowdfunding idea after being told that the 16 students who opted for GCSE Latin next year wasn’t a big enough group. “I thought, what I need is a big pot of money so that I can negotiate with our leaders and say, ‘you pay this much and I’ll pay the rest’,” continued Gina.