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).

After returning to Poland, he took up the job of deputy secretary in the Ministry of Foreign Affairs in Warsaw.

His home, in the village of Mloszowa, near Trzebinia, was ransacked by the Germans, who also burned Szembek's personal library.