Mn2+-doped (K,Na,Li)(Nb,Ta,Sb)O3 lead-free piezoelectric ceramics have been prepared by a conventional sintering technique. The effects of Mn2+ doping on the phase structure, microstructure and ferro-piezoelectric properties of the ceramics have been evaluated. MnO doping modifies the (K,Na,Li)(Nb,Ta,Sb)O3 structure, giving rise to the appearance of a TTB-like secondary phase and to changes on the orthorhombic to tetragonal phase transition temperature. The modification of this temperature induces a reduction of the piezoelectric constants, which is accompanied by an increase on the mechanical quality factor. Mn2+ ions incorporate into the perovskite structure in different off ways depending on their concentration.