In four studies, I examine the motives for employee silence. In Study 1, I examine open-ended survey responses to determine the nature and scope of silence motives. Study 2 develops measures of these motives and explores their factor structure. Study 3 refines the measures and provides confirmatory evidence of factor structure. Study 4 examines relationships between the new measures and related factors (employee voice, psychological safety, neuroticism, extraversion). Results indicate that six dimensions of silence motives (ineffectual, relational, defensive, diffident, disengaged, and deviant) emerged from the data, which can be reliably measured and provide incremental value for understanding and assessing employee silence. Copyright © 2012 John Wiley & Sons, Ltd.