The concept of ummah embodies the universalism of Islam and provides a framework for religious unity, which accommodates the cultural diversity of believers. It is an important part of historical as well as contemporary discourse on Islam. This paper provides an overview of the development and evolution of the concept of ummah and its usage in Islamic discourse to explain the current social, political and economic conditions of the Muslim world. It reports the findings about ummah consciousness and its relationship to modernity in Muslim countries of Southeast Asia, South and Central Asia, and the Middle East. It will examine the impact of globalisation on the Islamic ummah and how it is shaping the emerging struggle between 'hybridity' and 'authenticity' among Muslims and Islamic movements. The paper will explore the challenges of this struggle and its sociological implications for the 'de-centering' of the Muslim world into multiple autonomous regions. It will argue that the future of the Muslim ummah may gain strength not as a unified and unitary community, but as a differentiated community consisting of ummahs representing different Islamic regions. Each regional ummah will possess and embody a unique character that has been moulded by the history and temperament of its people. The paper will conclude with some observations on the future religious, intellectual, economic and political trajectories of Muslim countries.