The DOD community has adopted Distributed Interactive Simulation (DIS) as a base for an evolving suite of standards to support virtual battlefield representation. At present, DIS-based applications have focused on relatively small-scale exercises involving less than 1000 manned simulators and computer-generated forces (CGF). Current estimates of 10,000 to 100,000 entities to support simulation of theater-wide operations may exceed the capabilities of existing computational hosts and interconnection networks. This paper presents strategies for using massively parallel processors to simulate large numbers of synthetic forces using a contemporary synthetic forces software system (ModSAF). Alternative functional decompositions of the software are presented which map to specific parallel programming paradigms. Factors are identified which constrain candidate implementation paths. Partitioning and filtering techniques are discussed which can be used to reduce or eliminate broadcast packet distribution in a message-passing system. Data distribution, partitioning, and locking techniques are presented to support use of private, near-shared, and globally-shared memory on a true shared-memory system. Test implementations of a parallel ModSAF designed to run on the Convex Exemplar and Cray T3D MPP systems are described and benchmark results for specific tests are presented.