Glycerol dry reforming (GDR) to syngas was studied on Ni/ZrO2, Ni/La2O3 and Ni/La2O3–ZrO2 catalysts for elucidating the effects of support material on catalyst performance. A methodology was proposed to quantify the produced H2O, which was not reported so far in the GDR literature. At 750 °C, molar inlet CO2–to–glycerol vapor ratio (CO2/G) of 1–3 and residence time of 0.25 mgcat.min/Nml, the average CO2 and glycerol conversions were ordered as 13 % (NiLZ) > 10 % (NiZ) > 9 % (NiL) and 93 % (NiLZ) > 89 % (NiZ) > 83 % (NiL), respectively. NiLZ, the most active catalyst, also delivered > 95 % of the pertinent thermodynamic CO2 conversion at 0.5 mgcat.min/Nml. The 24 h stability of NiL and NiZ catalysts depended strongly on the inlet CO2 concentration. At CO2/G = 2, NiL deactivated by ∼5 % which was doubled at CO2/G = 4 mainly due to coking shown by TGA and Raman spectroscopy. The catalyst also suffered from Ni agglomeration as revealed by SEM–EDX and XRD. NiZ catalyst lost ∼21 and ∼9 % of its initial activity after 24 h aging at CO2/G = 2 and 4, respectively. Despite insignificant coking and sintering, XPS analyses pointed out almost four–fold decrease in the surface atomic Ni concentration on NiZ at CO2/G = 2 and suggested partial blockage of Ni sites by increased reducibility of monoclinic ZrO2 support at the less oxidative, CO2–lean environment. Regardless of the atmosphere, the NiLZ catalyst showed excellent stability features comparable to those of the notably higher–priced Rh and Ru–containing counterparts.