在大型多人角色扮演遊戲 (massively multiplayer online role-playing game, MMORPG) 中,為什麼有人願意知識分享呢?本研究以計畫行為理論為基礎,探討玩家在遊戲中知識分享的動機,包含利他主義、成就需求、期望報酬、期望貢獻、期望關係。計畫行為理論之主觀規範以行為規範表示,兼容描述性規範與命令性規範;而知覺行為控制以自我效能為主。最後,玩家的自我效能與社會價值傾向是否對知識分享態度影響知識分享意圖具有調節效果。 本研究以網路問卷方式執行,共回收 273 樣本,其中 235 個有效樣本。統計結果分三個部分顯示如下:第一,關於知識分享之動機與知識分享態度之關係,如利他主義與期望關係呈正向顯著;成就需求呈負向顯著;期望報酬與期望貢獻皆不顯著。第二,行為規範對於知識分享態度與意圖皆有正向顯著關係。知識分享態度、自我效能與社會價值傾向對於知識分享意圖有正向顯著關係。第三,關於知識分享態度對知識分享意圖的協調效果。自我效能之調節效果呈負向顯著;而社會價值傾向之調節效果則不顯著。 ;This study investigates the reasons why players are willing or unwilling to share knowledge in massively multiplayer online role-playing game, MMORPG? Based on the Theory of Planned Behavior, TPB, this study explores the motivation of knowledge sharing intentions among players in games. Self-efficacy and social value orientation are identified as moderators. The motivation of knowledge sharing includes altruism, need for achievement, expected rewards, expected contributions, and expected relationship. The subjective norm of TPB is instead of the behavioral norm which is combined with the injunctive norm and the descriptive norm. Self-efficacy is substituted for the perceived behavioral control in TPB. This study carried out a web-based questionnaire, and collected valid data from 235 respondents, out of a total of 273 samples. Results analyzed with PLS reveal three findings as follows. First, on motivation of knowledge sharing, altruism and expected relationship have positive effects on attitude of knowledge sharing, while need for achievement has significant but negative effect on attitude of knowledge sharing. Second, behavioral norm have positive effects on both attitude and intention of knowledge sharing. Attitude of knowledge sharing, social value orientation and self-efficacy have positive effects on intention of knowledge sharing. Third, on moderating effects, self-efficacy is found to moderate the relationship between attitude of knowledge sharing and intention of knowledge sharing.