El Ouriachi, who has represented Spain at youth level and has been called up by Morocco's Under-23 squad, could make his first appearance in the Potters' Asia Trophy game against Everton in Singapore on Wednesday.
The Barclays Premier League side have not announced the length of the 19-year-old's contract
"Stoke City are pleased to confirm they have completed the signing of Moha El Ouriachi and he could make his first appearance for the Club in today's Barclays Asia Trophy tie," the club said in a statement on their official website.
"Moha turned down Barcelona's offer of a new contract in favour of a move to the Potters, where he links-up with ex-Barca players Bojan and Marc Muniesa.
"Moha is now clear to figure in the Asia Trophy game against Everton in Singapore, which kicks-off 6pm local time (11am BST)."
Stoke chief executive Tony Scholes added: "He's excited about joining a Premier League club, especially one that already has two former Barcelona players in their squad.
"Moha has seen the progress made by Bojan and Marc and wants to try and do likewise."
Source : PA
Source: PA