The shrinkage of oxidation‐induced stacking faults (OSF′s) in silicon has been studied in the temperature range of 950–1100 °C in nitrogen ambient. Abnormally fast OSF shrinkage with activation energy of 2.3 eV has been observed at the initial stage of annealing. This fast shrinkage regime becomes more pronounced as the annealing temperature is reduced. It is proposed that the fast OSF shrinkage rate is due to the fact that initially the shrinkage is dominated by the rate of self‐interstitial capture at the silicon/silicon dioxide interface, while the subsequent lower rate with activation energy of 4.3 eV is due to the traditionally accepted diffusion‐limited mechanism. Because of the difference in activation energies, as temperature increases above about 1100 °C the latter mechanism becomes dominant and the fast shrinkage regime disappears.