We review the progress that has taken place in the past 30 years in the field of modeling insect epizootiology. The use of linked linear first-order differential equations dominated the early research and much of our theory today is based upon these simple continuous, non age-structured models of disease in insects. The major interactions explored with these models have been relationships between density of infective insect hosts, susceptible host densities, and time to death of infected insects. This modeling approach has been usefully applied to many insect/pathogen systems, especially for describing virus spread within gypsy moth populations. Computer simulation models have provided the framework for exploring the biological complexities inherent in epizootics. Recent studies have focused on the effects of weather and other environmental factors and the behavioral interactions of host and infected insects. In addition, the spatial dynamics of insect epizootics is at the forefront of much of the modeling be conducting now.