Use of the World Wide Web (WWW) for transfer of information and ideas is increasingly popular. Java, a programming language for the WWW, provides a simple method of distributing platform-independent, executable programs over the WWW. Such programs allow the expansion of WWW-based computational and analytical tools that support and enhance the existing WWW environment. However, a WWW-based, generalized simulation package is not yet available. Current literature motivates development of a general, WWW-based simulation package with maximum user interactivity and cross-platform capabilities. Advantages of such a package are discussed and explored in three potential applications. Main advantages are wide availability, controlled access, efficient maintenance, and increased integration. Disadvantages, such as variable download times, are also discussed. Netsim, a general, WWW-based simulation package written entirely in Java, is developed and demonstrated. Netsim provides complete model creation and modification capabilities along with graphical animation and data output. Netsim uses the event graph paradigm and object-oriented programming. Java, event graphs and objectoriented programming are discussed briefly. The Java random number generator is verified for uniformity and independence. Netsim is compared to SIGMA, a non-Internet simulation package, using a standard M/M/1 queueing model. Comparison issues and results are discussed. Additionally, tested through hand-tracing for coding validity, Netsim performs as theory prescribes. Netsim documentation and user’s manual are included. Netsim allows expandability for complex modeling and integration with other Java-based programs, such as graphing and analysis packages. Current Netsim limitations and potential customization and expansion issues are explored. Future work in WWW-based simulation is suggested.