Research on the relationship between prejudice and discrimination has been carried out within the more general framework of the early studies on the connection between attitude and behaviour (LaPiere, 1934; Wicker, 1969). While that literature specifies "when" attitudes predict behaviour (Zanna, Olson, & Fazio, 1980) and presents some hypotheses on "how" this process occurs (Snyder, 1982), the literature on the prejudicediscrimination link still reveals some shortcomings in these matters (Fiske, 2000). In fact, the few studies concerning the "when" question have shown that the prejudice-discrimination correlation has a moderate magnitude (Dovidio, Brigham, Johnson, & Gaertner, 1996), and that this correlation depends on several moderators (Schutz & Six, 1996). To our knowledge, our previous studies are the first simultaneously addressing both the "how " and "when" questions (Pereira, et al., in press; Pereira, et al., 2009), predicting that the psychological processes through which prejudice leads to discrimination involve justifying factors, such as threat perception. According to our theorising, legitimisation is a core concept to understand discriminatory actions (Allport, 1954; Tajfel, 1984). Legitimisation refers to the ways through which attitudes and behaviours can be justified. Nonetheless, some assumptions used as a base for several theoretical models conceptually support our proposal. For instance, research on aversive racism proposes that the availability of a non-racist justification facilitates the discrimination (Gaertner & Dovidio, 2005). An explanation for such effect has been proposed within the justification-suppression model of prejudice (Crandall & Eshleman, 2003), which suggests that discrimination depends on a justification that allows the individual to express prejudice without being socially sanctioned or threatening their self-concept of being fair and unprejudiced. System justification theory explains that this is possible because there is a general motive to justify the status quo (Jost and Banaji, 2001). According to social dominance theory (Sidanius and Pratto, 1999), justifications may occur through legitimising myths, since these myths maintain the hegemony of dominant groups over dominated groups. Extending this process to contribute to the understanding of the relationship between prejudice and discrimination, we demonstrate how prejudice can elicit the search for justifications to legitimise discrimination into anti-discrimination norm contexts (Pereira, et al., 2009). Threat Perceptions as legitimising factors for discrimination Realistic and symbolic threat perceptions constitute examples of justifications for discrimination (Crandall & Eshleman, 2003). Realistic threats are threats to the economic and political power and the well-being of the ingroup. Symbolic threats refer to how values perceived as different challenge the ingroup's worldview (Stephan, et al., 2002). The relationship between threat perceptions and prejudice was already studied in the frame of several theories and models (Bobo, 1999; Esses, Jackson, and Armstrong, 1998; Sherif, 1966; Stephan, et al., 2002; Zick, Pettigrew, and Wagner, 2008). Correlational studies have supported these models showing that both realistic and symbolic threat (Sears & Henry, 2003; Stephan, et al., 2002) predict prejudice. However, even longitudinal studies have shown that general threat feelings cause dislike towards outgroups (Schlueter, Schmidt, & Wagner, 2008), the causal relation between symbolic or realistic threat and prejudice is not yet fully supported (Riek, Mania, & Gaertner, 2006). According to our theorizing, however, prejudice cannot only derive from threat perception, it also can be a predictor of threat perceptions, i.e., it seems logical to see a stimulus (i.e., the outgroup) as threatening if any negative image (i.e., prejudice) about this stimulus has already been established. Moreover, it is probable that the more an outgroup is seen as a threat, the more legitimated will be behaviours against the members of that outgroup, i.e., threat perceptions will mediate the relationship between prejudice and discrimination. Indeed, this threat perception should be a mediator in the relationship between prejudice and discrimination, since it can be regarded as a justifying factor of discrimination (Crandall and Eshleman, 2003; LaPiere, 1936), especially when the social context condemns discrimination. In fact, our previous research provided experimental support for this hypothesis, showing that a prejudiced representation of Turkish people influenced participants' opposition to Turkey's adhesion to the EU (Pereira, et al., 2009). More importantly, we found that the psychological process through which this effect occurred involved a symbolic threat perception. In this sense, symbolic threat mediated the relationship between prejudice and opposition to Turkey's entry into the EU. Furthermore, when participants were placed in an egalitarian normative context, they experienced a dilemma and used symbolic threat as a justification for discrimination. This dilemma was absent when the prevalent norms were permissive (i.e., meritocratic). In such a context, no justification was needed to discriminate. We interpreted these effects based on the idea that if discrimination persists in democratic societies, despite the pressure of a normative standard that condemns prejudice, then to discriminate against someone based on prejudice must be psychologically incoherent. Thus, in these societies, the relationship between prejudice and discrimination needs to be justified (Pereira, et al., in press; Zick, et al., 2008). Taking these results together, we now raise two new questions: a) how do different types of threat legitimate the prejudice-discrimination relationship?; b) what is the role of the ingroup identification and justice concerns in this legitimising process?