National cultures influence expatriation at the company policy level, and they also affect the assumptions, values and behaviour of those individuals who are involved in the process. The doctoral study aimed to address the following objectives: (1) To determine what effects cultural differences have on expatriation practices at the company as well as at the individual levels; (2) To assess whether there is evidence for the convergence of expatriate practices among the countries included in the study; (3) To classify potential conflict situations in expatriate-local interactions in Russia; and (4) To determine which acculturation mode expatriates follow, and whether and how company practices facilitate an integrative mode of acculturation In Stage One a mail survey looked at the company level and examined the cultural influence on 136 multinationals' expatriate policies and practices in four countries: Germany, Japan, the United Kingdom and the United States. At first, descriptive statistics were calculated for the individual countries as well as for the total sample. Following that, I examined whether there was evidence for the convergence of expatriate practices. In Stage Two a qualitative field study focused on the expatriate assignment, and studied culture's effects on work interaction between expatriates and locals. The areas of inquiry included communication issues, such as using foreign language at work, the locals' use of telephone, written communication and presentations; and managerial issues, including motivation, providing positive and negative feedback. The 87 semi-structured interviews aimed to identify potential conflict situations in expatriate-local interactions as well as to assess the expatriates' and locals' acculturation modes. In order to be able to identify and analyse potential conflict situations, two models were developed: (1) The "Cultural Acceptability Model" is proposed as a tool for assessing the acceptability of individuals' behaviour from other cultures' point of view; (2) The "Model of Sources of Misunderstandings in Expatriate-Local Interaction" puts forward four factors as main determinants of conflict situations in expatriate-local interactions: cultural differences, economic developmental differences, the interacting parties' flexibility and openness to new cultures and the interacting parties' knowledge of each other's culture and language.