Carbon dioxide laser synthesis from gaseous precursors has been successfully applied to produce nanosized Al2O3 particles. Trimethylaluminum [Al(CH3)3] and nitrous‐oxide (N2O) were used as gas phase reactants. Ethylene (C2H4) was added as sensitizer gas. The as‐synthesized powder particles showed considerable carbon contamination and an amorphouslike structure. After thermal treatment at 1200–1400 °C, the powder transformed to hexagonal α‐Al2O3 with very low carbon contamination, confirmed by x‐ray diffraction, x‐ray photoelectron spectroscopy, and chemical analysis. The thermally treated powder was composed of spherical single‐crystal nanoparticles with a mean size 〈D〉 of 15–20 nm, as determined by x‐ray diffraction, electron microscopy, and Brunauer–Emmett–Teller specific surface measurements. The laser synthesized Al2O3 particles are suitable dispersoids for intermetallic alloy technology.