The return on investment of employer wellness programs has been heavily debated in recent years, yet existing research has failed to adequately assess the psychological factors that motivate program participation and how participation relates to organizationally relevant employee attitudes and behaviors. Using data over a 3-year period, we found beliefs about the value of employee wellness programs and perceived organizational support (POS) for wellness to be linked to wellness program participation through the mediation of intention to participate in the wellness program. Those with greater wellness participation were found to have higher performance ratings, higher job satisfaction, higher intention to stay, and lower turnover. However, the effects for job satisfaction and intention to stay disappeared when controlling for prior levels of satisfaction and intention to stay in cross-lagged models. Implications for scholars and practitioners are discussed.