The rate of thermal oxidation of silicon is orientation dependent indicating that the surface orientation is an important parameter in the kinetic mechanism. However, it has not been clearly established which properties of the silicon surface control the oxidation rate. This study uses five silicon surface orientations to investigate the effect of the density of silicon atoms on planes parallel to the surface and the effect of intrinisic oxide stress on the oxidation rates. At temperatures of 700°, 1000°, and 1100°C the initial order of the rates is . The crossover in rate to was observed at 700° and 1000°C, but not at 1100°C. A qualitative correlation is obtained between the order of the initial rates and the density of atoms on the five planes. Stress effects do not appear to be dominant in the thickness regime before the rates on the (110) and (111) orientations crossover, but the 1100°C results suggest that the crossover may be related to the development of intrinsic oxide stress at lower temperatures. A revised explanation of the crossover on the (110) and (111) orientations based on a stress‐related decrease in the transport of oxidant to the interface is proposed.