While current research shows that the gender gap in science achievement has disappeared (Miller, Blessing, & Schwartz, 2006), girls continue to show declining levels of STEM (science, technology, engineering, and math) engagement in school. Literature shows that various societal and educational factors impact girls’ STEM motivation disproportionately to boys (Bennett & Hogarth, 2009; Breakwell & Robertson, 2001; Brotman & Moore, 2008; Campbell & Clewell, 1999; Cokadar & Kulce, 2008; Huebner, 2009; Jovanovic & King, 1998; Lee, 1998; Miller, Blessing, & Schwartz, 2006; Osborne, Simon, & Collins, 2003; Solomon, 1997). The onset of this phenomenon occurs in the middle school years (AAUW, 1994; Bennett & Hogarth, 2009; Brotman & Moore, 2008; Galton, Gray, & Ruddock, 2003; Murphy & Whitelegg, 2006; Scantlebury & Baker, 2007; Solomon, 1997) and is compounded throughout high school and beyond by additional barriers, including societal stereotypes and mismatched values between females and the STEM community (Davis, 2001; Davis, 2002; Hill, Corbett, & St. Rose, 2010; NRC, 2007; Solomon, 1997). Ryan and Deci’s Self-Determination Theory (2000a, 2000b) provides a meaningful framework to explore this phenomenon by asserting that the conditions of relatedness, autonomy, and competence must be present for an individual to experience intrinsic levels of motivation. Science classrooms allowing students to work in cooperative groups on tasks that offer a high level of autonomy and an appropriate level of scaffolding could thus provide an optimum scenario for increased motivation. Yet, individuals must also feel that they are legitimate members of these groups (relatedness) in order for the condition to have a positive effect on motivation. According to the Stereotype Inoculation Model (Dasgupta, 2011a), individuals are more likely to show motivation in a particular domain when they can identify with their in-group peers, especially when those peers are also viewed as experts. This model posits that gender majority may provide this condition for girls in small science groups, allowing them to transcend stereotypes that have inhibited their STEM engagement and creating a scenario in which they are better able to view their possible selves as members of that group, thus increasing their levels of motivation within that context.