In the globalised world of the 21st century, issues of food and nutrition labelling are of pre-eminent importance. Several international bodies, including the World Health Organisation and World Trade Organisation, are encouraging countries to harmonise their food and nutrition regulations with international standards, guidelines and recommendations such as those for Codex Alimentarius. Through harmonisation, these organisations envisage fewer barriers to trade and freer movement of food products between countries, which would open doors to new markets and opportunities for the food industry. In turn, increased food trade would enhance economic development and allow consumers a greater choice of products. Inevitably, however, embracing harmonisation brings along cost implications and challenges that have to be overcome. Moreover, the harmonisation process is complex and sporadic in light of the tasks that countries have to undertake; for example, updating legislation, strengthening administrative capabilities and establishing analytical laboratories. This review discusses the legislation and regulations that govern food and nutrition labelling in Southeast Asia, and highlights the discrepancies that exist in this regard, their origin and consequences. It also gives an account of the current status of harmonising labelling of pre-packaged foodstuffs in the region and explains the subsequent benefits, challenges and implications for governments, the food industry and consumers.