<p>For decades the primary focus of language policy research has been activities by states and their agencies, while language policy activities in workplaces have attracted little attention. Addressing this gap, explicit and implicit dimensions of language policies are investigated in financial institutions operating in the globalised context of international banking in multilingual Luxembourg. Three complementary theoretical frameworks are used to extend language policy research to include not just explicit aspects of language policy (language policy statements), but also implicit aspects (the language practices and beliefs of a community). Spolsky's (2004) theory is used to identify and analyse three components of language policy (management, practices and beliefs); Language Management Theory (LMT) (Jernudd and Neustupny, 1987) is used to explore one specific component of language policy (management), and Shohamy's (2006) framework is used to explore the complex interaction between management, practices and beliefs. The data base for the study comprised two phases: the first phase involved interviews with managers in ten Luxembourg banks regarding language policy, followed in the second phase by questionnaires and focus-group discussions with employees from three case study banks regarding language use and beliefs. This empirical data suggests that even in banks where English has been formalised as the working language, multilingual mechanisms (recruitment and language courses) contribute to employees' practices effectively creating, a top-down multilingual implicit (de facto) policy. The data from international banks in Luxembourg suggests that a flexible approach to language management is useful in workplaces where communication is complex, multi-faceted and dynamic. The bottom-up perspective indicates that employees at international banks use English as a lingua franca (ELF) alongside other languages, negotiating language choice across speech communities and linguistic repertoires, for transactional and relational purposes. These multilingual employees highly value English as the most common language in banks for including and involving all, highlighting its vital role in banks. Because the data provides a strong argument for the consideration of both top down and bottom up perspectives, the results have theoretical significance for our understanding of language policy. Overall, this thesis provides insights into the complex nature of language policy in multilingual workplaces, including the importance of both top-down and bottom-up pressures on language practices, the crucial role of ELF and the relevance of attitudes towards ELF and other languages at local and global levels of management.</p>