Aleksandras Stulginskis (February 26, 1885 Kutaliai, Šilalė district municipality near Tauragė, Lithuania, Russian Empire; September 22, 1969 Kaunas) was the second President of Lithuania (1920–1926). Stulginskis was also acting President of Lithuania for a few hours later in 1926, following a military coup that was led by his predecessor as President (Antanas Smetona) and which had brought down Stulginskis' successor, Kazys Grinius. The coup returned Smetona to office after Stulginskis' brief formal assumption of the Presidency.

He began his theological studies in Kaunas and continued in Innsbruck, Austria. However, he decided not to become a priest and moved to the Institute of Agricultural Sciences in University of Halle. He graduated in 1913 and returned to Lithuania. There he started to work as a farmer. He published many articles on agronomy in Lithuanian press. In 1918 he started to publish the journals Ūkininkas ("Farmer") and Ūkininko kalendorius ("Farmer's Calendar").

During World War I he moved to Vilnius. He was one of the founders of the Lithuanian Christian Democratic Party and the head of its Central Committee in 1917. He signed the memorandum for the president Woodrow Wilson, addressing the question of the recognition of the Lithuanian statehood by the U.S.. Contrary to the Antanas Smetona's views, Stulginskis was oriented towards the Entente. He was one of the co-organizers of the Vilnius Conference. After that, he was elected to the Council of Lithuania. On February 16, 1918 he signed the Act of Independence of Lithuania. He was an advocate of democratic republic as the form of the Lithuanian state. Thus, he strongly opposed the idea of monarchy (actually, Mindaugas II was the King of Lithuania from 11 July to 2 November 1918). In independent Lithuania Stulginskis was in charge of organizing the national army to defend the country against the aggressions of Bolsheviks and Poles.

He served many times as a minister, during May 1920-1922 he was Speaker of the Constituent Assembly of Lithuania. During 1922-1926 he was the President of Lithuania. Stulginskis was Speaker of the Seimas 1926-1927.

He withdrew from politics in 1927, and worked on his farm. In 1941 Stulginskis and his wife were arrested by the Soviet NKVD and deported to a gulag in the Krasnoyarsk region, while his wife was deported to the Komi area. After World War II in 1952 he was officially sentenced by the Soviet authorities to 25 years in prison for his anti-socialist and clerical policies in pre-war Lithuania.

Released after Joseph Stalin's death in 1956, he was allowed to emigrate, yet he refused and returned to Lithuanian SSR. Stulginskis settled in Kaunas, where he died on September 22, 1969, aged 84.