The purpose of this study was to describe the conceptual foundation of cultural intelligence (CQ) as well as validation of the 20-item, four-factor Cultural Intelligence Scale (CQS). This study empirically examined the relationship between CQ and its antecedents (personality, IQ, emotional intelligence, international experience, and language ability), and further provided a theoretical model of future study that explores how CQ impacts the cross-cultural adaptation and assignment performance of expatriates. Analyses of the empirical findings demonstrated that each of the four factors of CQ (metacognitive CQ, cognitive CQ, motivational CQ and behavioral CQ) was influenced by the other variables such as personality, emotional intelligence, language ability, and international experience in significant yet varying degrees. General mental ability (IQ) did not relate to the four factors of CQ. The empirical findings also supported an incremental and predictive validity that CQ increased explained variance of cultural adaptation, over and above demographic characteristics, personality, general mental ability, emotional intelligence, language ability, and international experience. Based on these empirical results, this study proposed a theoretical model of CQ and discussed the direction for future research.