The 26-year-old has signed a four-year deal with the Spanish side, who have inserted a 30million euro (£21.5million) buy-out clause in his contract, after undergoing a medical on Thursday morning.
"Sevilla FC and Stoke City have reached an agreement for the transfer of midfielder Steven Nzonzi, who arrived in Seville on Wednesday night," said a statement on sevillafc.net.
"The player has signed for four seasons and will have a buyout clause of 30 million euros."
In a short statement Stoke added: "Stoke City can confirm that Steven Nzonzi has left the Britannia Stadium to join Spanish side Sevilla in a £7million deal.
"The club would like to place on record it's thanks to Steven and offer him our best wishes for the future."
Source : PA
Source: PA