At the beginning of the XXIst century there were many scientific works which addressed different aspects of the political system development in the Grand Duchy of Lithuania. The study of the political system in the GDL is based on the traditions established by Belarusian, Ukrainian, Lithuanian and Polish researchers of the XIXth - XXth centuries. They formed the certain areas of research, which continue to develop in the modern historiography. Despite the diversity of works, science is far from a single comprehensive study, which would combine the history of the political system in the Grand Duchy of Lithuania into a single system.