The Manchester United boss follows Cristiano Ronaldo, Lionel Messi and Neymar to have been called before the courts.
A Madrid prosecutor revealed today that a claim of two counts of tax fraud in 2011 and 2012 have been filed from when Mourinho was in charge of Real Madrid.
Mourinho took over as Manchester United manager last season and is yet to comment.
But United have vowed to back their man.
A United source said: “The manager has the club’s full backing and can count on our support.”
It is alleged Mourinho failed to declare income from the use of his image rights in order to get an “illicit benefit”.
A statement from the Spanish prosecutor’s office said: “The economic crimes department of the Provincial Prosecutor’s Office of Madrid has filed a complaint in the courts of Pozuelo de Alarcón against José Mourinho.
“He is accused of committing two crimes against the Public Treasury during the years 2011 and 2012 for a Total amount of €3,304,670.
“This investigation was initiated in the Public Prosecutor’s Office after the State Agency of the Tax Administration informed the Prosecutor’s Office of this information.
“From now on it will be the judge who is in charge of the case who must carry out the necessary steps to determine the possible responsibilities of Mr. Mourinho.”
Last week it emerged Ronaldo had been charged with tax evasion totalling around £13m.
He has been summoned to testify on July 31 in a case in which he is accused of hiding income from tax authorities.
He denies the allegations and sources close to the striker reckons he is so livid about the situation that he wants to quit Spain.
The news has sparked a massive transfer scramble, with United, Paris Saint Germain and a host of Chinese clubs keeping close tabs on the situation.
But Ronaldo himself has not admitted he wants to leave Real, and Express Sport understands Mourinho has big reservations about bringing him back to Old Trafford.
