The article overviews recent developments in research into national innovation systems (NIS). The article shows the diverse ways in which the concept of the national innovation system is defined. Most of these definitions emphasize the importance of institutional conditions. The existing literature also provides a variety of interpretations when it comes to the components of a national innovation system. Generally speaking, there are two definitions of innovation systems, the author says, a narrow definition and a broad definition. The narrow definition presents an innovation system in terms of ties and collaboration between the main players in the innovation process – the science sector, public and private R&D institutions and large corporations. The broad definition, on the other hand, covers all the aspects of the economic structure and institutional setup that influence learning as well as “searching and exploring” – the production system, marketing system and the financial system. The article interprets the essence of these systems in terms of how they function. The author also shows their various aspects, typology as well as gaps and shortcomings in theoretical concepts. It highlights important differences between these systems. There are differences in how innovation systems are defined and how their components are interpreted, the author says. This is largely because national economies differ in terms of the structure of production and institutional systems. However, certain characteristics of national innovation systems are impervious to change and remain country-specific, according to Gorynia-Pfeffer. The author uses a number of research methods including literature review to compare innovation systems and highlight differences between them, including those related to terminology. The article emphasizes the importance of national innovation systems despite the growing popularity of ideas to establish regional, sector-specific or technological systems. Various researchers have asserted that the process of knowledge creation and innovation is a collective process that requires the cooperation of many actors. Innovation is the outcome of interaction of multiple actors and the result of synergistic and collective action rather than individual initiative, Gorynia-Pfeffer concludes.