This paper aims to study the buckling and bending analysis of curvilinearly stiffened plates by using an isogeometric approach. First-order shear deformation theory is adopted to model the behaviors of stiffened plates. Based on the employed approach, it is easy to model stiffeners with different sizes and layouts, since the degrees of freedom for the whole structure are integrated into those of the original plate leading to a relatively low computational cost. The performance of the proposed approach is validated via a couple of benchmark problems available in the literature, and the effect of different parameters including bending stiffness, relative mass, cross section, and shape of stiffener on the buckling and bending behavior of curvilinearly stiffened plates is investigated. The results show the relative high accuracy of this method using fewer degrees of freedom for stiffeners, which is beneficial in optimization procedures.