Joe Sweeney, who teaches religious education at St Benedict's High School in Linwood, is fighting for his life at the Southern General Hospital in Glasgow.
It is believed the 45-year-old was cycling to work when he collided with a Ford Mondeo vehicle on Wednesday at High Street, in Johnstone, around 8.40am.
Police say Mr Sweeney's condition is "life-threatening" after he suffered a major head injury during the accident.
He was taken to the Royal Alexandra Hospital in Paisley before being transferred to the Southern General Hospital where he underwent an operation yesterday (Thursday).
Prayers have flooded in for the popular teacher, with pupils and colleagues taking to social media to wish him a speedy recovery.
Mrs Elizabeth Munro, acting head at St Benedict's, posted a message on the school's website, which reads: "On his way to St Benedict's, Mr Sweeney was involved in a road accident. He is in the Southern General Hospital. Please remember him in your prayers."
Anyone who witnessed the accident or has information is urged to contact Police Scotland by phoning 101.
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