The nucleation and growth of oxide scale at the early stages of oxidation of Ti 3 AlC 2 ceramics was studied via oxidizing at 1100°C in air for short times (≤900s). The nucleation of nanosized Al 2 O 3 particles mainly occurs at the ledges of the fractured lamellar Ti 3 AlC 2 grains as well as on the {0001} basal surfaces. The Al 2 O 3 nuclei mainly grow along these ledges to form oxide strings, and then spread on the terraces and the {0001} basal surfaces. An oxide layer consisting predominantly of nanosized α-Al 2 O 3 forms after oxidizing for 180s. The formation of lenticular hexagonal pores in Ti 3 AlC 2 grains is attributed to the faster consumption of Ti, Al and C atoms along 〈1 1 2¯ 0〉 direction than along 〈0001〉 direction. With further oxidation, rutile-TiO 2 particles form on top of the α-Al 2 O 3 layer, and grow to form a rutile-TiO 2 layer. Further oxidation leads to the formation of pores underneath the primary α-Al 2 O 3 layer. In this porous layer both Al 2 O 3 and TiO 2 were present with a preference for Al 2 O 3 to stay adjacent to the inward moving interface of Ti 3 AlC 2 substrate.