Highly rectifying semimetal graphite/ZnO Schottky diodes with a low-ideality-factor (1.08 at 300 K) were investigated by temperature-dependent current-voltage measurements. The current transport was dominated by thermionic emission between 300 and 420 K and the extracted barrier height followed the Schottky-Mott relation. A Richardson constant (A** = 0.272 A cm⁻²K⁻²) extracted from the Richardson plot shows nearly linear characteristics in the temperature range 300–420 K.