The tutorial system at Oxford and Cambridge is fundamental to methods of teaching at those universities, but it is by no means particular to them; Heythrop College (University of London), for instance, also offers a tutorial system with one-on-one teaching.
At the two campuses of St. John's College, U.S. and a few other American colleges with a similar version of the Great Books program, a "tutorial" is a class of 12-16 students who meet regularly with the guidance of a tutor.