A wind turbine blade (10, 610) for a rotor of a wind turbine (2) having a substantially horizontal rotor shaft is described. A surface mounted device (70, 70′, 170, 270, 370, 470, 570, 670, 770) is attached to a surface of the wind turbine blade (10). The surface mounted device (70, 70′, 170, 270, 370, 470, 570, 670, 770) is attached to the surface of the wind turbine blade (10, 610) via at least a first attachment part (77, 77′), which is connected to a part of the surface mounted device (70, 70′, 170, 270, 370, 470, 570, 670, 770). The attachment part (77, 77′) comprises a flexible housing (80, 80′, 680, 780) that forms a cavity (81, 81′, 681, 781) between at least the housing (80, 80′, 680, 780) and the surface of the wind turbine blade (10, 610). The cavity (80, 80′, 680, 780) is filled with an adhesive that provides an adhesive bonding to the surface of the wind turbine blade (10, 610).