This study describes the Virtual Programmable Logic Controller (Virtual PLC), a web-based system for PLC education that consists of (1) educational simulations to help students visualize abstract concepts, practice programming and device interfacing skills, and understand problem-solving processes; and (2) a simple intelligent tutoring system. Results from two preliminary evaluations are also presented. Index Terms-PLC, intelligent tutoring system, simulation, manufacturing engineering education. (c) 2005 Wiley Periodicals, Inc. Comput Appl Eng Educ 13: 266-279, 2005; Published online in Wiley InterScience (www.interscience.wiley. com); DOI 10.1002/cae.20052