Employee silence is an important element of social interaction that has a proactive nature with an intent and purpose. Nevertheless, the prevailing view was that silence is a problematic behavior which undermines the performance of organization and its members. Whereas previous research tends to emphasize the negative effects, this study explores the positive aspects of employee silence. Focusing on prosocial silence which is aimed at protecting or benefiting peers, supervisors, or organizations by withholding information, the first purpose of this study is to investigate its effects on generalized self-efficacy and the quality of LMX. Further, this study suggests the agreeableness and honesty-humility as personality moderators intervening in these relationships and seeks to explain who can bring out stronger positive effect through prosocial silence. From the data analysis of 246 members in 27 organizations, results showed that prosocial silence had a positive effect on the quality of LMX. However, its effect on generalized self-efficacy was not significant. In addition, the hypotheses on the moderating effects of agreeableness between prosocial silence and two dependent variables were supported. Unlike the expectation, the moderating effect of honesty-humility was significant only for LMX, in the opposite direction.