Steponas Kairys (; 1879 in Užnevėžiai near Ukmergė – 16 December 1964 in Brooklyn) was a Lithuanian engineer, nationalist, and social democrat. He was among the 20 men to sign the Act of Independence of Lithuania on 16 February 1918.
Engineering career
Born in the Anykščiai district, then in Imperial Russia, Kairys graduated from the Institute of Technology in Saint Petersburg. Due to conflicts with the academic administration concerning his participation in student clubs and dissident demonstrations, his studies were intermittently interrupted. Following graduation he worked for several years in railroad construction in the Samara and Kursk regions of Russia. He returned to Lithuania in 1912 and worked on city sanitation and water supply systems in Vilnius, and following the Polish occupation of the city left to the temporary capital of Lithuania, Kaunas. After 1923, he taught at the University of Lithuania in Kaunas, The council was formed by the conference to declare and establish independence of Lithuania. The task, however, was extremely tough because of the German Wehrmacht presence in the state. The Germans promised to recognize the state if the council agreed to form a firm and permanent federation with Germany. The council issued a declaration to that effect on 11 December 1917. However, Germany did not keep its word and did not recognize the state. The council was torn apart and Kairys with the three others socialists withdrew on 26 January 1918. However, on 16 February 1918 they returned to sign the Act of Independence of Lithuania. The act did not mention anything in specific about relations to Germany.
The council proceeded to negotiate with Germany, which now demanded to void the 16 February decision and recognized the state based on the 11 December declaration. On 13 July 1918, the council, in hopes to avoid being incorporated into a personal union with the Hohenzollern dynasty, elected Mindaugas II as King of Lithuania. This was unacceptable for Kairys and he left the council, this time permanently. However, he remained active in the politics: he was elected to the Constituent Assembly and all three Seimas before the coup d'état of 1926.