In today’s organizations, the spread of team-based, horizontal cultures has increased both the frequency and significance of coworker interactions. However, empirical understanding of how perceived coworker support influences employees’ performance-related behaviors remains limited. Integrating social exchange theory and power-dependence theory, this study investigates the impact of perceived coworker support on two forms of employee performance−task performance and voice behavior−and explores the moderating role of job embeddedness in these relationships. Specifically, it is hypothesized that perceived coworker support positively influences both task performance and voice behavior, but that high job embeddedness may serve as a constraint, weakening these associations. To test these hypotheses, a survey of employees and their supervisors was conducted, and 188 matched cases were used for the final analysis. The results revealed that perceived coworker support was significantly associated with voice behavior but not with task performance. Furthermore, the positive effects of coworker support on both task and voice behaviors were significantly weakened−even reversed−when employees reported high levels of job embeddedness. These findings contribute to a more nuanced understanding of coworker support and shed light on the potential downside of job embeddedness, offering implications for organizations aiming to enhance employee performance.