A mixed marriage is a marriage between persons of different nationalities, races, or religions. This research takes a case study of marriages that occur between Indonesian and Polish, classified as a mixed nationality marriage. This research aims to find out how spouses can achieve effective intercultural communication competence in an Indonesian-Polish marriage. The researcher focuses on the process of intercultural communication in an Indonesian-Polish marriage and expects to find out the problem that might happen in a mixed marriage that could affect daily life. This research was conducted by using qualitative methodology also with semi structured interviews as data collection techniques. Since the amount of empirical research in a study about mixed marriage is limited, this research is expected to help people who go through mixed marriages that run into miscommunication or misunderstanding and expected to know how to overcome barriers and resolve specific issues in their marriage life. The scope of this research is not only limited to married people but intended for every society, including how to develop and maintain friendships or other relationships between persons with different cultures.

Keywords: Intercultural Communication, Mixed Marriage, Indonesian, Polish, Mixed Marriage Culture