It is commonly recognised that commercial security, in its different forms, has become an important element in societies as a provider of private and public security. The reasons for this development are manifold but can be seen to well from the changes in individual societies and their governance structures. Because of the growth of the security industry, many regulatory regimes have considered some form of industry regulation to be necessary. Some private security research has been carried out during the last 40 years. Most of the published texts have handled the situation in individual countries. The published studies are in most cases theoretical and based on existing documentary sources. In this study local interviews in six regulatory regimes; Belgium, Estonia, New York, Queensland, South Africa and Sweden, as well as transnational sources are used to make comparisons of different regulation solutions. There is, however, a basic problem with definitions, vocabulary and statistics concerning private and commercial security. A common platform is missing, which means that in this study some basic elements have been defined in order to be able to make structured analyses. The existing situation and interview comments concerning private security regulation have been used to analyse the industry, its challenges and its future development. The thesis tries to answer the questions why, what/who and how to regulate in general and more specifically in the six chosen regulatory regimes. Many of the industry’s challenges and trends can be understood through an examination of existing systems of private security regulation: legal apparatus that reveals how commercial security is positioned in different societies. The findings of this thesis confirm that private as well as commercial security regulation is very much a ‘command and control’ and ‘top-down’ procedure, bound to the general situation in each individual regulatory regime, and reflecting the cultures of the societies. The regulation texts as such may look quite similar, but the actual reasons for and practical implementations of them are locally specific and related to individual states’ overall governance practices and administrative maturity.