Bolesław II of Cieszyn (Polish: Bolesław II cieszyński, Czech: Boleslav II. (Těšín), German: Boleslaus II. (Teschen); c. 1425/28 – 4 October 1452), was a Duke of Cieszyn since 1431 (until 1442 with his brothers as co-rulers), ruler over half of Bielsko and Frysztat (from 1442), and during 1452 sole ruler over one half of Bytom.
He was the fourth and youngest son of Duke Bolesław I of Cieszyn by his second wife Euphemia, daughter of Duke Siemowit IV of Masovia.
After the death of his father in 1431, Bolesław II ruled over the duchy together with his brothers as co-rulers, but under the tutelage of their mother. After the division of the duchy on 29 November 1442, he still held the title of Duke of Cieszyn, but in practice ruled only over 16 towns and villages in Cieszyn; the most important of them was Frysztat, which was obtained by Bolesław II only after his mother's death in 1447 and shortly after, received broader city rights by Bolesław II. He left most of the control over the duchy to his brother Przemyslaus II.
Just like his brothers and father, also Bolesław II tried to be active in the international politics. Unlike his brother Władysław, who was allied with Bohemia, Bolesław II maintained close ties mainly with the Kingdom of Poland. In 1443 he supported Poland in his conflicts with Hungary, and in 1449 he was appointed judge in the disputes between King Casimir IV and the Bohemian nobility. However, Bolesław II's good relations with Poland didn't prevent the sale of the Duchy of Siewierz to Zbigniew Oleśnicki, Bishop of Kraków, which resulted in a war at Upper Silesia, who lasted until February 1447.