The heat capacity of Liquid Al-La-Ni alloys was measured using an adiabatic calorimeter. The heat capacities C-p(x,T) exhibit large temperature and composition dependences. The results indicate the existence of a maximum in the C-p(T)-curve in the undercooled melt. An association model was applied to calculate the thermodynamic mixing functions of ternary liquid Al-La-Ni alloys using the model parameters of the three Limiting binary systems and assuming an additional ternary association reaction. The calculations show a good agreement with the experimental enthalpy of mixing and the C-p(x,T)-data.