Many researchers investigated the efficacy of using worked examples in classroom instruction and provided evidence in the effectiveness of worked example instruction in mathematics, computer programming, physics, and etc. However, there are limited studies in worked example design. The purpose of this study is to generate the instructional design principles of worked examples. After reviewing the empirical studies dealing with worked example in the last two decades, eight principles are identified in this study, (a) imagination principle, (b) completion principle, (c) fading principle, (d) process principle, (e) presentation principle, (f) media principle, and (g) timing principle, (h) self-explanation principle. Future research suggestions are also provided.