The thermal and photochemical reactions of (CH3)(3)Ga and O-3 have been explored using a combination of matrix isolation, infrared spectroscopy, and theoretical calculations. Experimental data using twin jet deposition and theoretical calculations demonstrate the formation of multiple product species after deposition, annealing to 35 K, and UV irradiation of the matrices. The products were identified as (CH3)(2)GaOCH3, (CH3)(2)GaCH2OH, (CH3)(CH3O)Ga(OCH3), (CH3)(2)GaCHO, and (CH3)Ga(OCH3)(CH2OH). Product identifications were confirmed by annealing and irradiation behavior, O-18 substitution experiments, and high level theoretical calculations. Merged jet deposition led to a number of stable late reaction products, including C2H6, CH3OH, and H2CO. A white solid film was also noted on the walls of the merged (flow reactor) region of the deposition system, likely due to the formation of Ga2O3.