This thesis investigates the construction of 'national unity' within the culturally diverse society of Malaysia. Specifically, it aims not only to understand how 'national unity' is constructed by the ruling elites but also how these dominant frames are contested and negotiated by people of different ethnic groups. Indeed, the issue of 'national unity' in Malaysia is controversial and complex. The country faces ongoing challenges, many related to the divisive legacies of the British colonial system; its recent history has been marked by struggles around questions of ethnicity, nationalism, elite power, and the status accorded to ethnic Malays -the Bumiputera, or 'People of the Soil' -post-independence. On the other hand, the country is well-known for its cultural heterogeneity and Drawing on framing as the theoretical and methodological framework for this research, the objectives of this study are firstly, to examine how 'national unity' is constructed through these PSAs, and secondly, to explore the intended audiences' perceptions of those PSAs and the frames underpinning these perceptions. To achieve these outcomes, the research develops a framing analysis of a 102-item sample of PSAs in the form of print, broadcast, and online media promoting 'national unity' and social cohesion, published by the Malaysian government between 2009 and 2014. The results of a series of six focus groups representing the three major ethnic groups in Malaysia -Malays, Chinese, and Indian -are also analysed, using a framing approach. The findings suggest that multiple, often conflicting frames are involved in making sense of 'national unity'; contested narratives of nationhood and ethnic identity are identified as central themes in the analysis. In specific, the Government's construction of 'national unity' discovered two dominate: nationalism frame and multiculturalism frames, while audience's construction of 'national contested ii these frames at times and added a different, oppositional frame: political frame. These findings reinforce the importance of understanding processes of strategic communication in complex, multicultural contexts, involving multiple actors with competing ways of framing the issue. Indeed, the possibility of genuine social cohesion relies on understanding and addressing this very complexity.iii