Drawing on sociometer theory, we argue that when 360 degree feedback is used in a work setting, being ostracized by coworkers has a stronger negative influence on employees' state self‐esteem, which promotes interpersonal deviance and demotivates helping directed toward coworkers, as compared to settings in which 360 feedback is not used. We tested our hypotheses using data collected from North American employees (Study 1) and a two‐wave survey of employees in China (Study 2). Results from both studies support the hypothesized interaction between workplace ostracism and 360 degree feedback on interpersonal deviance and helping behavior. Results from Study 2 further show that lower state self‐esteem accounts for the stronger negative association of ostracism with helping behavior among employees who are exposed to 360 degree feedback. Ostracism is not related to subsequent state self‐esteem or behavior when 360 degree feedback is absent. We discuss the implications for theory and research concerning employee exclusion. Copyright © 2016 John Wiley & Sons, Ltd.