With the purpose of improving the dielectric and piezoelectric properties of (K 0.5 Na 0.5 )NbO 3 (KNN), a multiple doping strategy was tested in this research. Piezoceramics with composition (K 0.5 Na 0.5 ) 0.94 Li 0.06 0.97 La 0.01 (Nb 0.9 Ta 0.1 )O 3 were prepared by the traditional ceramic method. The calcined powders were sintered in their own atmosphere at 1,100 °C for 1.0, 1.5 and 2.5 h. X-ray diffraction analysis showed that the Li + , La 3+ and Ta 5+ cations diffuse into the KNN structure to form a perovskite-structured solid solution. For 1 h sintering time, a dominant orthorhombic phase is obtained, whereas for the longer times, the dominant phase was tetragonal. The presence of a tetragonal tungsten–bronze minority second phase is confirmed. Scanning electron micrographs show rectangular-shaped grains with a mean size of 1.1 ± 0.2 μm. The existence of pores and traces of a liquid phase favoring grain growth and homogeneity is also observed. Experimental results show an enhancement of the permittivity associated with the enlargement of the c parameter of the cell that increases with sintering time. Li + incorporation into the structure is made evident by its transition temperature at 400 °C different from those of KNNLaTi (81–110 °C) and KNNLaTa (340 °C). An analysis of the phase transition of the samples indicates a normal rather than a diffuse transition. The electromechanical parameters k p , Q m , σ p , s 11 , d 31 and g 31 are determined and compared to those of commercial PZT ceramics.