St Wilfrid’s Catholic High School and Sixth Form College in Featherstone said its financial position as “very serious” in a letter to staff last month.
It comes after the school predicted its projected deficit in two years time could be more than £950,000.
The academy has now launched a two phase consultation to review its staff structure to make savings.
In the letter seen by the Express, the school said to meet the required savings it could axe up to 23 members of staff.
Teachers met with trade union representatives to express their concerns.
One member of staff, who asked not to be named, said: “Some children are taking their GCSEs this year. It is a very important time for them.
“It is important parents and staff know what is going on at the school.”
The first phase of the consultation will see the school identify potential savings and develop a new staff structure.
The second phase will then see the school identify the number of staff that will be made redundant.
The letter revealed that the school’s projected deficit for 2015/16 was £359,722. The figure could rise to £648,898 by the following year and then to £952,420 by 2017/18.
It said: “These figures alone make it clear that urgent action needs to be taken to ensure a positive budget. The academy simply cannot afford for the current level of staffing costs to continue.”
The school said a review of its staff structure had not been carried out for a number of years and it had instead employed more teachers as it became an academy.
St Wilfrid’s acting head teacher Helen Gilroy said: “It is our priority to ensure that St Wilfrid’s can offer the best possible education to its students, now and in the future.”
“We have started a consultation with staff and trade unions about the future shape of the academy and are fully committed to working closely with all colleagues.
“I would like to reassure parents and students that St Wilfrid’s will continue to deliver the highest standard of learning, care and support to those at our school.”
St Wilfrid’s Catholic High School and Sixth Form College became an academy in November 2012.
The academy forms a part of the Bishop Konstant Catholic Academy Trust, which runs nine primary schools and one other secondary school.
The school has been left without a permanent headteacher since David Lewis left his post in October last year.