This dissertation examined the acculturation processes from the host society point of view. The theoretical background drew on intergroup relations models of Cross-Cultural and Social psychology and attempted a synthesis of ideological, intergroup and existential parameters in the acculturation processes for the host society members. Four studies were carried out to investigate the influence of ideological, existential and intergroup parameters on the acculturation expectations of the host society towards immigrants in general and distinct immigrant groups. In Study 1 (N = 401 students and employees), the acculturation expectations for immigrants were examined. The most desirable acculturation expectation for immigrants was Individualism and Integrationism, while the less desirable was the Assimilationism. Acceptance of social dominance was negatively associated with Individualismism and positively with Assimilationism and Exclusionism while right-wing authoritarianism was negatively correlated with Integrationism-transformation and positively with Segregationism. Blatant and latent racism were associated with the negative -with regard to the intergroup outcome- expectations of Assimilationism, Segregationism and Exclusionism. It was found that mortality salience has a moderating role in the above correlations through the increase of the contribution of blatant racism to the prediction of the acculturation expectations and the decline of the contribution of latent racism. In Study 2 (N = 420 students), the role of sociopsychological parameters in the acculturation expectations for Albanians, Americans and Pakistani immigrants in Greece was investigated. Differentiation between the expected and the perceived acculturation strategies among valued and devalued immigrant groups was identified. In addition, a different intergroup outcome emerged in terms of intercultural convergence: a more frequent occurrence of the consensus model for Americans and Albanian immigrants on the one hand, and the conflictual and problematic model for Pakistani immigrants on the other. Ideological, existential and intergroup parameters predicted the acculturation expectations differently per immigrant group. A strong predictive factor was the acceptance of social dominance. As expected, constructive patriotism predicted Integration, while - contrary to what was expected - blind patriotism predicted multicultural ideology. In Study 3 (N = 450 students), acculturation expectations for an undervalued immigrant group (Pakistani) at both intergroup and interpersonal levels were investigated. In terms of acculturation orientation, the Greek participants reported a higher preference for adopting the language and values of the host country by Pakistani immigrants, as well as for maintaining the morals and customs, the citizenship and the religion of the immigrant group. Acculturation expectations were different at the interpersonal and the intergroup level. Significant predictive factors at both levels were social dominance orientation and perceived intergoup threat. In Study 4 (N = 529 students), acculturation expectations for Albanian and Pakistani immigrants and Syrian refugees were investigated. Significant differentiation regarding the contribution of ideological, intergroup and existential parameters to the prediction of acculturation expectations according to the studied migrant group was found. For the Albanian group, statistically significant predictive factors for acculturation expectations were variables related to economic parameters (intergroup competition, economic uncertainty, realistic threat). For the Syrians, significant predictive factors were prejudice (for Individualism and Assimilation) and realisitic threat (for Exclusionism and Integrationism-transformation). Finally, for the Pakistani group, intergroup competition and perception of intergroup threat emerged as predicting factors. In this target group Exclusionism was significantly predicted by most of the intergroup parameters (blind patriotism, contact, realistic threat, prejudice and latent racism). In sum, through the analyses per group and overall, strong predictive indicators were intergroup parameters, in particular intergroup threat and contact.