A device for levelling tiles includes a traction member having a base which can be inserted below two or more of the tiles which are adjacent at mutual edges, and a C-shaped element extending from the base, the free ends of its wings being associated with the base. The device further includes a wedge having a surface with a serrated profile for interaction with the traction member at an edge of the core of the C-shaped element. The wedge is insertable inside the C-shaped element of the traction member between the wings thereof.