Jan Szembek (11 July 1881 – 9 July 1945) was a Polish diplomat, one of the most influential ones in the final years of the Second Polish Republic and a close associate of Józef Beck.
Szembek was born in a szlachta family on 11 July 1881 in the village of Poręba, near Alwernia. He graduated from the Vienna University and took up the post of an Austrian government clerk in Bosnia (1905-1908). In 1908, he settled in Kraków.
In 1919, after Poland regained independence from the partitions of Poland, Szembek was named chargé d'affaires and later he was the Polish ambassador in Budapest (1921-1924), Brussels (1925) and Bucharest (1927), where he remained until 1932. After returning to Poland, he took up the job of deputy secretary in the Ministry of Foreign Affairs in Warsaw.
After the invasion of Poland, he left Poland on 17 September 1939, along with other members of the government. His home, in the village of Mloszowa, near Trzebinia, was ransacked by the Germans, who also burned Szembek's personal library. He died on 9 July 1945 in Estoril, near Lisbon.
