The 55-year-old had been accused of owing the state nearly €3.3m in undeclared image rights revenue for 2011 and 2012, which accumulated during his time as Real Madrid manager.
In response, Mourinho insisted he had paid all the taxes he owed from his time in Spain, which came to an end in 2013.
But according to Spanish media outlet El Mundo, Mourinho agreed on Tuesday to pay a €2m fine and received a suspended one year sentence.
Those close to Mourinho, however, have insisted no prison time was imposed or accepted.
Lionel Messi, Cristiano Ronaldo and Luka Modric are all among those who play in Spain to have encountered similar disputes with the law over financial matters.