Rossington high in Doncaster, Emmanuel high in Nottingham and Sir Thomas Boteler high in Warrington bring the number of Anglican secondaries in England to 193.
"Our school had quite a strong Christian ethos already," said John Sharples, head of Sir Thomas Boteler. "Now we hope to strengthen the religious and collective-worship aspects."
He added it would be a gradual process so as not to cause offence to non-Christian pupils and staff.
Canon John Hall, general secretary of the Church of England board of education, said the conversions were a step towards achieving last year's Dearing Report goal of creating 100 new Anglican secondaries.
He added that the schools will not turn away local children without religious commitment.