Recent studies experimentally examine employee decisions to participate in new corporate ventures (Monsen, Patzelt, & Saxton, in press; Monsen, Saxton, & Patzelt, 2007), however, they do not distinguish between risk and uncertainty. Entrepreneurial decisions are more often made under uncertainty rather than “risky certainty” (Alvarez & Barney, 2005). Therefore, using risk-related theories, including agency (Jones & Butler, 1992), utility maximization (Douglas & Shepherd, 2000, 2002), and expectancy theories (Gatewood, Shaver, Powers, & Gartner, 2002) is questionable. Extending corporate entrepreneurship studies (Monsen, 2005; Monsen & Boss, 2009), we examine corporate venture opportunities from the social identity perspective (Ellemers, de Gilder, & Haslam, 2004; Tajfel & Turner, 1986) to explain an employee’s willingness to accept more uncertainty and to act more entrepreneurially for their employer (compare, Sauner-Leroy, 2004; Wright & Cordery, 1999).