The mol-ecule of the title compound [systematic name: 2-(4-tert-butyl-benz-yl)isoindoline-1,3-dione], C(19)H(19)NO(2), is V-shaped with a dihedral angle of 74.15 (7)° between the mean planes of the phthalimide unit and the benzene ring. The methyl groups of the tert-butyl substituent are disordered over two sets of positions, with an occupancy ratio of 0.700 (4):0.300 (4). In the crystal, inter-molecular C-H⋯O hydrogen bonds link adjacent mol-ecules into centrosymmetric dimers. An additional weak C-H⋯O contact, together with weak C-H⋯π and π-π inter-actions [centroid-centroid distance = 3.961 (2) Å] generate a three-dimensional network.