Behavioural, attitudinal, cognitive and personality traits factors have been recognized as the main determinants of intercultural effectiveness. This paper argues for the need to recognize the plausibility that expatriates having similar behavioural, attitudinal, cognitive and traits characteristics may vary significantly in their intercultural effectiveness. This is because some expatriates may be effective or ineffective by chance or birth (ascribed rather than achieved). Therefore expatriates' 'socio-biographical' background, such as hisher ethnicity, age, nationality, educational qualification, profession (role) and religion, is noted as among the most significant factors that can impact on intercultural effectiveness. It is argued that these variables deserve serious attention given the diversity of expatriates from different national and ethnic backgrounds.