A wind turbine blade (1) comprising an outer casing formed at least in part of panels (3) of thermoplastic polymer composite, defining a leading edge (4) and a trailing edge (5) of the wind turbine blade, and at least one stiffening member (6) made of polymer composite, extending along a longitudinal axis (A) of the wind turbine blade inside said wind turbine blade (1), said stiffening member (6) being arranged between at least one panel defining the leading edge (4) and at least one panel defining the trailing edge (5), wherein the thermoplastic polymer composite comprises a fibrous reinforcement and a (meth)acrylic thermoplastic polymer matrix and in that at least one panel (3) of thermoplastic polymer composite is connected to the stiffening member (6) by a weld-type interface (7).