Na_1−<i>x</i>Li_<i>x</i>NbO₃ ceramics with composition 0.05≤<i>x</i>≤0.30 were prepared by solid-state reaction method and sintered in the temperature range 1100-1150 °C. These ceramics were characterised by X-ray diffraction as well as dielectric permittivity measurements and Raman spectroscopy. Dielectric properties of ceramics belonging to the whole composition domain were investigated in a broad range of temperatures from 300 to 750 K and frequencies from 0.1 to 200 kHz. The Rietveld refinement powder X-ray diffraction analysis showed that these ceramics have a single phase of perovskite structure with orthorhombic symmetry for <i>x</i>≤0.15 and two phases coexistence of rhombohedral and orthorhombic above <i>x</i>=0.20. The evolution of the permittivity as a function of temperature and frequency showed that these ceramics Na_1−<i>x</i>Li_<i>x</i>NbO₃ with composition 0.05≤<i>x</i>≤0.15 present the classical ferroelectric character and the phase transition temperature <i>T</i>_C increases as <i>x</i> content increases. The polarisation state was checked by pyroelectric and piezoelectric measurements. For <i>x</i>=0.05, the piezoelectric coefficient <i>d</i>₃₁ is of 2pC/N. The evolution of the Raman spectra was studied as a function of temperatures and compositions. The results of the Raman spectroscopy study confirm our dielectric measurements, and they indicate clearly the transition from the polar ferroelectric phase to the non-polar paraelectric one.Read less <