Lech Aleksander Kaczyński (18 June 1949 – 10 April 2010) was a Polish lawyer and politician who served as the Mayor of Warsaw from 2002 until 2005 and as the President of Poland from 2005 until his death in 2010.
Before he became president, he was also a member of the Law and Justice party. He was the identical twin brother of the former Prime Minister of Poland and current Chairman of the Law and Justice party, Jarosław Kaczyński. On 10 April 2010, he died in the crash of a Polish Air Force jet that occurred on a landing attempt at Smolensk North Airport in Russia.