To improve education regarding sustainability and green buildings, we designed a multiplayer (2-4 people) green building strategy game called GBGame to deliver knowledge of and introduce applied technologies for green buildings. To verify the game's learning effect, we conducted separate measurements using the ARCS motivation model and a paper-based exam among 72 students majoring in architecture. These students were divided into an experimental group (who played the game) and a control group (who underwent lecture-based instruction). Results indicate that (1) game players had stronger learning motivation than those who attended the lectures; (2) players who learned through the game generally exhibited better learning effectiveness than non-players; (3) following cross-validation, we discovered a highly significant correlation between the learning effect and players' attention, perception of relevance, confidence, and satisfaction during the game; and (4) the game system was found to be attractive to the students, implying that it can be an effective instructional and recreational material to use during green building education.