La3-xTe4 is a state-of-the-art high temperature n-type thermoelectric material with a previously reported maximum zT∼1.1 at 1273 K. Computational modeling suggests the La atoms play a crucial role in defining the density of states for La3-xTe4 in the conduction band. In addition to controlling charge carrier concentration, substitution with Ca2+ atoms on the La3+ site is explored as a potential means to tune the density of states and result in larger Seebeck coefficients. High purity, oxide-free samples are produced by ball milling of the elements and consolidated by spark plasma sintering. Powder XRD and electron microprobe analysis are used to characterize the material. High temperature thermoelectric properties are reported and compared with La3-xTe4 compositions. A maximum zT of 1.3 is reached at 1273 K for the composition La2.22Ca0.775Te4.