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Honeycombs are discrete materials at the macro-scale that can be used as standalone materials or placed as cores between composite facesheets to form sandwich structures. The prediction of their effective mechanical properties as a continuum material is essential to the analysis and design of honeycomb sandwich structures and other honeycomb structures. In this research work, the effective mechanical behavior of honeycombs was studied by analytical and numerical means and correlated with experimental results for aluminum hexagonal honeycombs. The analytical methods included continuum formulations and models based on strength of materials including a variety of beam theories. The numerical analyses included finite element analyses and the experimental program consisted of the mechanical characterization of the honeycombs under both in-plane and out-of-plane loading. The effective in-plane properties including elastic moduli and Poisson’s ratios of the honeycombs were studied as a function of their relative density with existing beam models. It was shown experimentally that the beam models describe well the material response in the direction of the honeycomb double wall. However, it was concluded that the effective elastic moduli for honeycombs with low relative densities are not similar in the two in-plane directions as predicted by previous studies. A refined model that predicts the effective honeycomb properties was developed to take into consideration the curvature that is present in the intersection points of hexagonal honeycombs due to corrugation or expansion during manufacturing. The developed refined model is not only capable of explaining the experimentally observed difference between the effective in-plane elastic moduli but can also be expanded to predict the effective moduli of honeycombs of any relative density.