Andrzej Ajnenkiel (born 21 February 1931 in Warsaw - died 10 April 2015 in Warsaw) was a Polish historian. He specializes in the political history of Poland and the history of Polish law, especially constitutional law.

From 1949 to 1954 Ajnenkiel studied law at the University of Warsaw. Since 1979 Ajnenkiel has been a professor at the Institute of History at the Polish Academy of Sciences in Warsaw. In 1991 he gained a professor degree, the highest academic degree in Poland, and later a habilitation. He has been a member and director of several historical societies, including the Polish Historical Society.

Works

• Historia ustroju Polski 1764-1939 (1969)
• Administracja w Polsce: zarys historyczny (Administration in Poland: Historical Overview) (1975)
• Parlamentaryzm II Rzeczypospolitej (1975)
• Od rządów ludowych do przewrotu majowego: zarys dziejów politycznych Polski 1918-1926 (1977)
• Polska po przewrocie majowym: zarys dziejów politycznych Polski 1926-1939 (Poland after the May Coup: Overview of the Political History of Poland 1926-1939) (1980)
• Polskie konstytucje (Polish Constitutions) (1991)
• Prezydenci Polski (Presidents of Poland) (1991)
• Konstytucje Polski w rozwoju dziejowym 1791-1997 (2001)