For the first time, the nonlinear bending behavior of porous functionally graded (FG) curved nanotubes is studied in this paper. The stiffness enhancement and stiffness reduction effects are described by the nonlocal strain gradient theory. The FG curved nanotubes have uniformly distributed pores in the radial direction. The material properties of the nanotubes corresponds to a modified power-law function. The asymptotic solutions of the curved nanotubes is obtained by using the two-step perturbation method. It shows that the nonlinear bending behavior of the curved nanotubes is influenced by the size effects, power law index, porosity distribution, temperature variation, boundary conditions, and physical dimension. Furthermore, the jump changes as well as snap-through buckling can take place when the FG curved nanotubes are under the influence of normal bending loads.