An oil filter, comprising: - a head having an oil inlet and an oil outlet (11,12); - a cup having an open end, coupled to the head; - a filtering element internal to the cup and defining an inner central chamber and an outer annular chamber, each one being provided with an open end (32b, 33a) connected to one of the parts of oil inlet and oil outlet (11, 12); - a top cap, having a central nozzle connected to the open end of the inner central chamber, a median annular portion closing the adjacent end of the filtering element and a peripheral portion, provided with windows and positioned on the open end of the outer annular chamber and seated onto the open end of the cup; - at least one rotational locking means and at least two axial locking means, which are incorporated to one of the parts defined by the open end of the cup and by the peripheral portion of the top cap, and - at least one rotational locking receiving means and at least two axial locking receiving means, provided in the other of said parts (21, 53) and in the interior of which are respectively fitted and retained the rotational locking means and the axial locking means, upon the seating of the peripheral portion of the top cap onto the open end of the cup, characterized in that - each axial locking means is defined by a projection, in the form of a rounded arrow axially projecting from the open end of the cup, and - two axial locking receiving means are provided, each of them being defined by an axial recess, with a contour corresponding to that of the projection and provided in a respective peripheral skirt segment, elastically deformable and incorporated to the top cap and turned to the filtering element. - a head having an oil inlet and an oil outlet (11,12); - a cup having an open end, coupled to the head; - a filtering element internal to the cup and defining an inner central chamber and an outer annular chamber, each one being provided with an open end (32b, 33a) connected to one of the parts of oil inlet and oil outlet (11, 12); - a top cap, having a central nozzle connected to the open end of the inner central chamber, a median annular portion closing the adjacent end of the filtering element and a peripheral portion, provided with windows and positioned on the open end of the outer annular chamber and seated onto the open end of the cup; - at least one rotational locking means and at least two axial locking means, which are incorporated to one of the parts defined by the open end of the cup and by the peripheral portion of the top cap, and - at least one rotational locking receiving means and at least two axial locking receiving means, provided in the other of said parts (21, 53) and in the interior of which are respectively fitted and retained the rotational locking means and the axial locking means, upon the seating of the peripheral portion of the top cap onto the open end of the cup, characterized in that - each axial locking means is defined by a projection, in the form of a rounded arrow axially projecting from the open end of the cup, and - two axial locking receiving means are provided, each of them being defined by an axial recess, with a contour corresponding to that of the projection and provided in a respective peripheral skirt segment, elastically deformable and incorporated to the top cap and turned to the filtering element.