West Yorkshire Police on Saturday said Thomas Mair, 52, has been charged with the murder of the 41-year-old, BBC reported.
She was shot and stabbed outside her constituency surgery in Birstall, West Yorkshire, on Thursday.
Mair will appear at Westminster Magistrates’ Court on Saturday and faces a number of other charges, including grievous bodily harm.
He is further charged with possession of a firearm with intent and possession of an offensive weapon, the force said.
Speaking on Friday, temporary Chief Constable Dee Collins said a 77-year-old man remains in a stable condition in hospital after he was injured when he “bravely intervened” in an effort to help the mother of two.
Vigils were held across the country on Friday evening as members of the public and politicians came together to lay flowers, light candles and stand in silence in memory of Cox.
Cox is the first sitting MP to be killed since 1990, when Eastbourne MP Ian Gow was the last in a string of politicians to die at the hands of Northern Irish terror groups.
She entered Parliament as MP for Batley and Spen in last year’s general election.