Prince Karol Stanisław Radziwiłł (Lithuanian: Karolis Stanislovas Radvila II, Exonym: Charles Stanislaus: 27 February 1734 – 21 November 1790) was a Polish–Lithuanian nobleman, diplomat and prince of the Commonwealth. He is frequently referred to by his well-known sobriquet Panie Kochanku ("My Beloved Sir") to distinguish him from his earlier namesake. Prince Radziwiłł held several important posts; from 1752 he was the Master Swordbearer of Lithuania, and in 1757 he became one of the first recipients of the Order of the White Eagle. From 1762 he was Voivode of Vilnius.
Radziwiłł was born on 27 February 1734 to General-Hetman Michał Kazimierz "Rybeńko" Radziwiłł and Princess Urszula Franciszka Wiśniowiecka and spent his childhood in Nieśwież, in the Grand Duchy of Lithuania, then part of the Polish–Lithuanian Commonwealth.