DC reactive magnetron sputtering was used for the deposition of Zr–Si–N thin films. Four series of samples have been deposited at various substrate temperatures TS: 300 K, 510 K, 710 K and 910 K. Depending on TS, different N2 partial pressures pN2 were required to obtain nearly stoichiometric ZrN films. Si content (CSi) was varied in each series by changing the power applied on the Si target, whereas the power on the Zr target was kept constant. The microstructure of the coatings was examined by XRD and in cross-section by transmission electron microscopy (TEM). Depending on TS and pN2, the deposition rate showed significant variations from 0.04 to 0.18 nm/s. The correlation between film morphology (preferential orientation of crystallites, grain size, column dimensions, thickness of the SiNx layer covering ZrN crystallites) and the deposition conditions (power applied on Si target, temperature, nitrogen partial pressure and deposition rate) provides useful information for optimizing the deposition process.