The increasing trend of international mobility has intensified intercultural communication and expanded the requirements expected from international managers. The whole expatriation process represents a costly matter for the engaged companies. Detecting determinants of the intercultural adaptation can significantly minimaze the risk of failure during the foreign assignment. Moreover, the consideration should already be given in the beginning when the selection of eligible candidates for expatriation is done. The research objective of the paper is to investigate the determinants of intercultural adaptation of expatriates with international assignment experience and consequently to understand the complexity of the adaptation process while working abroad. Firstly, theoretical background reviews previous studies on adaptation process and cultural distance, intercultural competences and motivation as important factors. Next, primary data were obtained from Czech expatriates via questionnaire regardless the country of their foreign assignment. Additionally, the final model of intercultural adaptation was developed by applying a systematic thinking approach as an appropriate method emphasizing links and backward dynamics between the elements. The model is based on interaction of six determinants; such as: intercultural competences, language skills, intercultural training, past intercultural experience, motivation and cultural distance; that were identified from primary and secondary research as the most crucial variables. The findings lead to deeper understanding of the processes and help to improve the selection process of suitable candidate for foreign assignment and the intercultural training in order to reach higher level of adjustment.