Trifluoromethylselenolation of arenes with [Me₄N][SeCF₃] in the presence of an oxidant through Pd-catalyzed C(sp²)–H activation under the assistance of a directing group is established for the first time. The reaction tolerates different directing groups and a variety of functional groups, enabling selective installation of a SeCF₃ moiety onto the ortho positions of arenes. Mechanistic studies revealed that the CF₃SeSeCF₃ intermediate in situ generated from oxidation of [Me₄N][SeCF₃] might be the real SeCF₃ reagent in the reaction.