<p>Addition of short carbon fibre (Cf) in ZrB₂-SiC composite promotes the formation of slender SiC grains network which has large ZrB₂/SiC interfacial area and gets fully oxidized even at lower temperature (~1300°C) and shorter exposure time (~30s) at the initial stage of oxidation. Lower temperature oxidation renders uniform ZrB₂ oxidation also. Thinnest SiC grains are fully oxidized in the beginning of oxidation since SiC oxidation starts from the ZrB₂/SiC interfacial area and move progressively towards the core region. This leads to formation of SiO₂ protective outer scale for Cf-added composite at the outset of oxidation at l.ower temperature and consequent mitigation of active SiC oxidation and internal oxidation at higher temperature (1625°C). On the other hand, the extent of uniform ZrB₂-oxidation is found to be more than SiC-oxidation for the coarser SiC grain bearing pristine composite (without Cf) at lower temperature (~1300°C). During lower temperature oxidation of pristine ZrB₂-SiC composite, uniform oxidation of ZrB₂ and partial oxidation (outer-SiO₂+inner-SiC) of coarser SiC grains occur which lead to formation of non-protective outer SiO₂ layer. Above 1500 °C, irrespective of its grain size SiC becomes more prone to oxidation than the ZrB₂ phase because of active SiC-oxidation. Cf addition to ZrB₂-SiC composite renders suppression of active SiC-oxidation by increasing CO partial pressure beneath the protective outer SiO₂ scale and consequently reduces SiC depleted region. However, pristine ZrB₂-SiC composite with coarser SiC grains shows larger SiC depleted region due to active SiC-oxidation and heavy internal oxidation at higher temperature (1625°C) beneath the non-protective outer SiO₂ scale.</p>