As the functionality and speed of 3-D geologic modeling software have improved over the last 30 years, it has become a core tool for identifying, understanding, and modeling the structural controls on ore deposits. This chapter attempts to summarize some of the key considerations involved in the 3-D modeling of structurally controlled ore deposits and establishes a basic three-step workflow that can be applied to almost any deposit style: establish a geologic framework through field work and 3-D visualization, model the project-scale geology, and finally identify, model, and understand the controls on ore shoots. Importantly, the geologic understanding of a project is not a static concept. Each step in the modeling process should add to it, highlighting which aspects of the model fit the current geologic understanding, and thus increase confidence, and which require further review and possible modification. This chapter also provides guidance on preparing data for 3-D modeling, basic 3-D visualization techniques, selecting a modeling approach, and model validation, as well as commentary on some of the more common pitfalls encountered in 3-D modeling. Finally, case studies of the Tuzon gold deposit in Liberia and the Yalea gold deposit in Mali are provided as examples of the process involved in building a 3-D geologic model, from field work to final model.