A joint member for panels, the joint member being intended to mechanically connect a first panel and a second panel to each other, the joint member being intended to be positioned in a position interposed between the first panel and the second panel, in a joint region in which a side or edge of the first panel is alongside a side or edge of the second panel, the joint member having a body equipped with at least four connecting portions (21, 22, 23, 24) each having a respective seat (31, 32, 33, 34) intended to receive a fixing element, the seats (31, 32, 33, 34) being spaced from each other and, in a plan view of the joint member, being positioned at the vertices of a quadrilateral, wherein a first and a second of said connecting portions form a first pair of connecting portions and are intended to be fixed to the first panel, and wherein a third and a fourth of said connecting portions form a second pair of connecting portions and are intended to be fixed to the second panel, each connecting portion (21, 22, 23, 24) having a first face which, in use, is facing the respective panel (51, 52), and a second face which is on an opposite side to the first face, said respective seat (31, 32, 33, 34) being, or comprising, a through hole which extends in a thickness of the connecting portion (21, 22, 23, 24) between the first face and the second face and which has a central longitudinal axis, the second face of the first connecting portion and the second face of the third connecting portion being on a same first side of the body, the second face of the second connecting portion and the second face of the fourth connecting portion being on a same second side of the body, opposite to the first side, whereby the central longitudinal axes of the seats (31, 32, 33, 34) of the connecting portions of the same pair are slanting relative to each other and have projections which, in a view orthogonal to said plan view, diverge in the direction coming out of the first faces, characterised in that, for the first pair (21, 22) and the second pair (23, 24) of connecting portions, the first faces of the connecting portions of the same pair between them form a housing (37, 38) which, in use, is intended to receive a region of the side or edge (511, 521) of the respective panel (51, 52). the joint member being intended to mechanically connect a first panel and a second panel to each other, the joint member being intended to be positioned in a position interposed between the first panel and the second panel, in a joint region in which a side or edge of the first panel is alongside a side or edge of the second panel, the joint member having a body equipped with at least four connecting portions (21, 22, 23, 24) each having a respective seat (31, 32, 33, 34) intended to receive a fixing element, the seats (31, 32, 33, 34) being spaced from each other and, in a plan view of the joint member, being positioned at the vertices of a quadrilateral, wherein a first and a second of said connecting portions form a first pair of connecting portions and are intended to be fixed to the first panel, and wherein a third and a fourth of said connecting portions form a second pair of connecting portions and are intended to be fixed to the second panel, each connecting portion (21, 22, 23, 24) having a first face which, in use, is facing the respective panel (51, 52), and a second face which is on an opposite side to the first face, said respective seat (31, 32, 33, 34) being, or comprising, a through hole which extends in a thickness of the connecting portion (21, 22, 23, 24) between the first face and the second face and which has a central longitudinal axis, the second face of the first connecting portion and the second face of the third connecting portion being on a same first side of the body, the second face of the second connecting portion and the second face of the fourth connecting portion being on a same second side of the body, opposite to the first side, whereby the central longitudinal axes of the seats (31, 32, 33, 34) of the connecting portions of the same pair are slanting relative to each other and have projections which, in a view orthogonal to said plan view, diverge in the direction coming out of the first faces, characterised in that, for the first pair (21, 22) and the second pair (23, 24) of connecting portions, the first faces of the connecting portions of the same pair between them form a housing (37, 38) which, in use, is intended to receive a region of the side or edge (511, 521) of the respective panel (51, 52).