The outbreak of 2019 Coronavirus Disease (COVID-19) has forced schools and universities around the world to adopt online learning. However, many educators are facing challenges because they do not have prior experience with online teaching and the transition happened rapidly. One effective way to keep students engaged and improve their learning is by using online simulation games. Simulation games provide opportunities for feedback and learning and can promote interdisciplinary and collaborative working styles. This research develops internet-based multiplayer interactive simulation games to teach manufacturing and supply chain concepts. The players in the supply-chain games include a customer, a manufacturer, an assembler, and a supplier. The simulation games are structured into three different parts: the backend server that handles the game logic, the client server that takes user input, and the database which stores the input information. The simulation involves producing car toys that satisfy customer requirements. A group of high school and community college educators tested the simulation games and provided feedback for improvement. The simulations were then deployed in the practice of high school and undergraduate classrooms. Feedback from teachers and students indicates that online simulations can improve effectiveness of teaching and learning.