In the title naphthalimide derivative, C(23)H(26)N(2)O(6), the 1,8-naphthalimide system is essentially planar [maximum deviation = 0.0456 (16) Å]. A characteristic pattern of alternating long and short C-C bond lengths is observed in the 1,8-naphthalimide unit. The mean planes through the methyl carbamate and acetic acid groups form dihedral angles of 42.30 (9) and 61.59 (9)°, respectively, with the 1,8-naphthalimide plane. In the crystal structure, inter-molecular O-H⋯O and C-H⋯O hydrogen bonds link neighbouring mol-ecules, forming R(2) (2)(9) hydrogen-bond ring motifs. These rings are further inter-connected by inter-molecular N-H⋯O and C-H⋯O hydrogen bonds into a three-dimensional supra-molecular network.