ENThe roots of the Lithuanian political system precede the emergence of the modern Lithuanian state in 1918 by several decades. For over a hundred years before independence, Lithuania was an integrated part of the imperial tsarist Russia, and in 1940–1991, a union republic of the USSR. After regaining independence in 1991, while shaping the new political system, the Lithuanian political elite decided to refer to the systemic and institutional patterns from the short period of the functioning of democratic governments in the First Republic of Lithuania. The aim of the study is to analyze the evolution of the Lithuanian political system and the individual elements influencing its changes in the years 1920–1926 and 1990–2020. As a result, it was possible to demonstrate the similarities and differences in particular periods of the evolution of democracy, which was extremely helpful in indicating the directions of development of political systems and their individual elements. Keywords: First Republic of Lithuania; Second Republic of Lithuania; party system; electoral system; constitution. [From the publication]