Leszek (Polish pronunciation: [ˈlɛʂɛk]) is a Slavic Polish male given name, originally Lestko, Leszko or Lestek, related to Lech, Lechosław and Czech Lstimir.

Individuals named Leszek celebrate their name day on June 3.

• Lestko
• Leszek I (disambiguation)
• Leszek II (disambiguation)
• Leszek III
• Leszek, Duke of Masovia (ca 1162–1186)
• Leszek I the White (1186/1187-1227)
• Leszek II the Black (1241–1288)
• Leszek Balcerowicz, a Polish economist, the former chairman of the National Bank of Poland and Deputy Prime Minister
• Leszek Bebło (born 1966), Polish long-distance runner, 1993 Paris Marathon champion
• Leszek Blanik, 2008 Olympic gold medalist in vault (gymnastics)
• Leszek Kołakowski (1927–2009), Polish philosopher
• Leszek Miller, former Prime Minister of Poland
• Sir Leszek Krysztof Borysiewicz, British academic and university administrator
• Leszek A Gasieniec, Professor of Computer Science at the University of Liverpool

• Lech (disambiguation)
• Polish name
• Slavic names