During Lithuania’s authoritarian period (1926–1940), the country underwent significant political, social, and economic shifts under the leadership of Antanas Smetona. His rise to power began with the 1926 coup d'état, which removed the democratically elected government amid growing dissatisfaction with its policies, such as signing the Soviet–Lithuanian Non-Aggression Pact. The coup was supported by conservative factions, including the Lithuanian Nationalists Union (Tautininkai) and Christian Democrats, with Smetona becoming president and Augustinas Voldemaras assuming the role of prime minister. However, Smetona soon consolidated power, sidelining even allies like Voldemaras, and ruling as an authoritarian leader until Lithuania’s occupation in 1940.
Smetona's regime dissolved the Seimas (parliament) in 1927, despite earlier promises to restore democracy. The political system transitioned towards centralized control, with political parties gradually banned except for the Lithuanian Nationalists Union. In 1928, Smetona introduced a new constitution that dramatically increased presidential powers. He began to foster a cult of personality, referring to himself as "tautos vadas" (Leader of the Nation). Smetona's government maintained strict control over public discourse and media, suppressing opposition efforts, including a failed leftist rebellion in 1927. Political tensions heightened with deteriorating relations between Lithuania and Nazi Germany, particularly over the Klaipėda Region, which Germany annexed in 1939, weakening Lithuania's economy and political standing.
Socially, Smetona's authoritarianism had a dual impact. Although the regime stifled political pluralism, it promoted national identity, culture, and education. The interwar period saw the establishment of Lithuanian-language institutions and the expansion of primary and secondary education. The arts, literature, and theater flourished, contributing to a sense of cultural pride. Urban demographics shifted as ethnic Lithuanians began to constitute the majority in cities that had traditionally been dominated by Jews, Poles, and Germans—an outcome of both emigration and growing nationalist policies.
However, tensions with Germany escalated, especially after the annexation of Klaipėda, which caused economic instability. This period also saw increasing pressure from Poland, resulting in the 1938 Polish ultimatum, which forced Lithuania to normalize diplomatic relations under the threat of military action. Lithuania accepted the ultimatum but remained in a precarious geopolitical position. By 1939, the Nazi-Soviet Molotov–Ribbentrop Pact placed Lithuania under Soviet influence, effectively sealing the fate of its independence.
Though Smetona’s regime managed to prevent extreme political movements from gaining traction, the dictatorship failed to prepare Lithuania for the geopolitical turmoil that followed. The authoritarian governance that limited civil liberties and political dissent ultimately left the country vulnerable to external pressures. In 1940, with Soviet forces poised to occupy Lithuania, Smetona fled the country, marking the end of the interwar period and ushering in an era of foreign domination.