A wind turbine blade defining a chord extending from a leading edge to a trailing edge of the wind turbine blade and a thickness extending in a direction transverse to the chord, the wind turbine blade comprising two or more blade sections (102,104,106) each of which defines a non-joint zone and, at one or each of its ends, a joint zone; wherein the blade sections (102,104,106) are connected in pairs such that the joint zones of each pair are connected at a joint, whereby the joint is positioned between two non-joint zones; wherein at least one of the joints has an increased thickness and a wider chord relative to the thickness and the chord of the two non-joint zones between which the joint is positioned so as to increase the second moment of inertia in the area of the joint; characterised in that: the geometrical shape of a cross-section of the wind turbine blade in the area of at least one of the joints is substantially the same as the geometrical shape of a cross-section of the wind turbine blade at a non-joint zone adjacent to the joint, such that the outline of either of the two cross-sections (134, 136) may be scaled to coincide with the outline of the other of the two cross-sections (136, 134); and in that: a first of the two joint zones of each joint, defines a distal zone and a second, of the two joint zones of each joint, defines a proximal zone relative to a hub of the wind turbine blade, and wherein: - the width of the chord in the area of the distal zone increases in the direction of the hub of the wind turbine blade; - the width of the chord in the area of the non-joint zones increases in the direction of the hub of the wind turbine blade; and - the width of the chord in the area of the proxim al zone decreases in the direction of the hub of the wind turbine blade. the geometrical shape of a cross-section of the wind turbine blade in the area of at least one of the joints is substantially the same as the geometrical shape of a cross-section of the wind turbine blade at a non-joint zone adjacent to the joint, such that the outline of either of the two cross-sections (134, 136) may be scaled to coincide with the outline of the other of the two cross-sections (136, 134); and in that: a first of the two joint zones of each joint, defines a distal zone and a second, of the two joint zones of each joint, defines a proximal zone relative to a hub of the wind turbine blade, and wherein: - the width of the chord in the area of the distal zone increases in the direction of the hub of the wind turbine blade; - the width of the chord in the area of the non-joint zones increases in the direction of the hub of the wind turbine blade; and - the width of the chord in the area of the proxim al zone decreases in the direction of the hub of the wind turbine blade. a first of the two joint zones of each joint, defines a distal zone and a second, of the two joint zones of each joint, defines a proximal zone relative to a hub of the wind turbine blade, and wherein: - the width of the chord in the area of the distal zone increases in the direction of the hub of the wind turbine blade; - the width of the chord in the area of the non-joint zones increases in the direction of the hub of the wind turbine blade; and - the width of the chord in the area of the proxim al zone decreases in the direction of the hub of the wind turbine blade. - the width of the chord in the area of the distal zone increases in the direction of the hub of the wind turbine blade; - the width of the chord in the area of the non-joint zones increases in the direction of the hub of the wind turbine blade; and - the width of the chord in the area of the proxim al zone decreases in the direction of the hub of the wind turbine blade.