Understanding cross-cultural aspects of emotional overinvolvement (EOI) on psychosis outcomes is important for ensuring cultural appropriateness of family interventions. This systematic review explores whether EOI has similar impact in different cultural groups and whether the same norms can be used to measure EOI across cultures. Thirty-four studies were found that have investigated the impact of EOI on outcomes across cultures or culturally adapted EOI measures. The relationship between high EOI and poor outcome is inconsistent across cultures. Attempts to improve predictive ability by post hoc adjustment of EOI norms have had varied success. Few studies have attempted a priori adaptations or development of culture-specific norms. Methodological differences such as use of different expressed emotions (EE) measures and varying definitions of relapse across studies may explain a lack of EOI outcome relationship across cultures. However, our findings suggest that the construct and measurement of EOI itself are culture-specific. EOI may not necessarily be detrimental in all cultures. The effect of high EOI may be moderated by the unexplored dimension of warmth and high levels of mutual interdependence in kin relationships. Researchers should reevaluate the prevailing concepts of the impact of family relations on the course and outcome of psychotic disorders, specifically focusing on the protective aspects of family involvement. Clinically, family interventions based on EE reduction should take cultural differences into account when treating families from different ethnocultural groups.