A teachers' union at a school in Bristol has spoken of an "atmosphere of fear" where "results are placed above the welfare of children".
The "entire teaching staff" at Our Lady of Lourdes Catholic Primary School "will leave at the end of the term", the Bristol Post has reported.
South Gloucestershire Council said it is aware of the concerns from the National Union of Teachers and "is willing to work with its representatives".
The school is yet to comment.
A spokeswoman for South Gloucestershire NUT said staff had complained that a "heavy-handed management style has caused so many teachers to be off with stress".
She added: "This rate of turnover is unacceptable. Children need consistency and stability. There should have been much stronger intervention once the situation was known."
Clifton Diocese would not comment but instead directed the BBC to South Gloucestershire Council.
A spokesman for the local authority said the newspaper figure of 16 staff leaving over the year is "misleading" as it includes temporary staff brought in to cover people leaving mid-year.
But he confirmed seven long-term teachers have resigned over the course of this year includes two moving to other schools, the acting head who is taking up promotion elsewhere, and one member of staff's fixed-term contract ending.
He added a new head has been appointed and will take up the post in January with leadership in the interim from the executive head.