Modern weapon systems have greatly expanded the range of options that can be exercised by trained tactical decisionmakers. However, tactical training environments today are unable to create the different opponent behaviors necessary to challenge the decisionmaking skills of tactical commanders. Since the use of human opponents is clearly not cost-effective, this training requirement falls under the purview of computer-based simulation. This paper presents a knowledge-based simulation approach for tactical adversary modeling along with an interactive user interface that allows non-programmers to modify simulation models on-line. A laboratory application that addresses a set of training objectives appropriate for surface warfare officer training is also included. The suggested approach is directly applicable to meeting current training simulation requirements generated by the surface Navy. Both the simulation approach and the software implementation are upward-compatible with the modeling of coordinated adversaries and supporting team members.