Several models exist for predicting indentation hardness in terms of uniaxial material properties, but they do not adequately cover the material properties and indenter geometries of interest. We have developed a family of models that can be used to model a variety of indentation processes, including conical indenters, spherical indenters, and Knoop and Vickers hardness tests. These models also are capable of predicting the hardness of a wide variety of elastic and plastic material properties, primarily in terms of a single parameter incorporating both the elastic and plastic properties. Using this parameter, the hardness model provides a simple, yet powerful, method for predicting material hardness from uniaxial properties. Comparisons with data have been excellent.