Olivine is a key mineral of mafic-ultramafic and metamorphic rocks. Oxygen isotopic composition of olivine has been widely used to decipher mantle processes, igneous differentiation, and fluid-rock interaction in metamorphic systems. Accurate in situ oxygen isotopic analysis of olivine by secondary ion mass spectrometry (SIMS) requires matrix-matched reference materials to correct instrumental mass fractionation and monitor the stability of instrument. In this study, we report two natural olivine reference materials, AOL (Fo: 91-97) and POL (Fo: 94-97), for in situ oxygen isotopic analysis. These samples exhibit homogeneous oxygen isotopic compositions, with a two-standard deviation of 0.33‰ (N = 105) and 0.37‰ (N = 105), respectively. The recommended δ1?O values, determined by laser fluorination isotope ratio mass spectrometry, are 5.52 ± 0.25‰ for AOL and 5.64 ± 0.13‰ for POL (all ± 2SD, N = 5). Combined with previously reported olivine standards, our results confirm that no significant matrix effects were observed within the forsterite (Fo) content range of Fo?? to Fo??, supporting the wide use of AOL and POL as reference materials for high?precision oxygen isotopic microanalysis.