In this article, an analytical model is derived to investigate the in-plane homogenized stress-strain relationship of an adhesively bonded commercial hexagonal honeycomb core under large deformation. The model incorporates some advanced features of the core cell such as cell wall curvatures, node bond adhesive layers, and adhesive fillets at the cell wall intersections in the analysis. Nonlinear homogenized results of the fiberglass/phenolic honeycomb core predicted by the analytical model are compared with test data as well as predictions from finite element models (FEMs) of both real and idealized (without modeling the node bond adhesive) core cells to investigate the effects of the node bond adhesive. Predictions of the analytical model are in good agreement with the test data and predictions of the FEM of the real core cell. Homogenized properties of the honeycomb core obtained from the analytical model at infinitesimal strains are compared with several analytical models from the literature. Adhesive peel stress is also calculated by the analytical model and compared with the FEM.