This study aims to investigate how cultural humility, cultural intelligence, moral concern, and self-direction relate to support for multicultural collaboration among 239 construction professionals in Palestine. Moreover, the study further investigates whether the broader norm climate (i.e., cultural tightness) changes the direction or strength of these links. Using a survey question approach for the purpose of data collection the study checks the measurement model quality in terms of reliability and validity and confirms that the model is valid on such statistical grounds. Moreover, through PLS-SEM approach,  the study found that cultural humility was the strongest positive predictor of support for multiculturalism; cultural intelligence and cultural tightness also showed clear positive effects, and moral concern added a smaller but reliable boost. However, it is important to note that the self-direction values have no significant relationship with the multiculture ideology. Regarding the moderation analysis, there is a significant moderating effect of Cultural Tightness on the relationship between Cultural Humility and Multicultural Ideology, and between Self-Direction Values and Multicultural Ideology. However, the moderating role of Cultural Tightness between Cultural Intelligence and Multicultural Ideology, and between Moral Foundations and Multicultural Ideology, is statistically insignificant. These results suggest practical steps for firms and project owners: set simple, shared rules; offer short, hands-on training that builds humility (listening, asking before assuming, acknowledging limits); strengthen everyday intercultural skills; and provide structured autonomy so independent problem-solving supports fair, rule-guided teamwork.