During periods of official nationalism in Thailand, the Thai media played a significant role in promoting government policy. The Thai media during those periods was a government orientated enterprise. However, the Thai parliament approved a new constitution in 1997 which aims to minimise state control over the media. It is for this reason that this thesis chose to study current events and the current situation. Once the media was opened up, the patterns of ownership started to change. The media, post 1997, began to change from a government orientated enterprise towards a market-orientated private enterprise. This thesis investigates the interaction between media and nationalism in Thailand. It looks at the relationship between media owners and political leaders in general. This thesis also looks at the signs, symbols, costumes, and messages that generate nationalistic feelings among audiences. This research was carried out by analysing the film contents. This analysis of content is used to demonstrate the hypothesis, which states that the new patterns of ownership of the media have led to new techniques for shaping nationalism. In order to do so, this thesis employs a media and nationalism framework which is created by using numerous theories on media and nationalism. The results have indicated that, although the primary motive of film-making may now be turning a profit, films which aim to promote the nationalism or political agendas still exist. It appears in several case studies that the private media owners and the political leaders share common interests. The filmmakers do not hesitate to use the symbols, cultures, and traditions, which are invented by the leaders. Symbols that represent power and legitimacy of the political leaders are promoted by an attempt of the filmmaker to persuade audiences that those practices and tradition, and by extension, the leaders are righteous. Individual films target different classes in Thai society, which vary by their beliefs, culture, and practices. The filmmakers are either making the film according to the culture of those classes to strengthen the nationalistic awareness from the audiences, or they are using their medium to persuade the audiences to accept their class values. Either way, it can be demonstrated that since the end of the period of official nationalism, nationalism is still promoted through film. This media support of political agendas can be seen as the new style to promote nationalism.