Johan Thyrén (1861–1933) was a Swedish academic and jurist who was influential in reforming the penal law of Sweden.

[2][1] On 7 June 1926 Thyrén was appointed minister of justice to the cabinet led by Premier Carl Gustaf Ekman.

[4] From 1932 to 1936 he collaborated with his cousin and minister of justice Karl Schlyter to develop a reform program.

[1] It was written upon the request of the Swedish government which asked him to formulate reforms in the criminal law in 1909.

[1] He was instrumental in the termination of the death penalty in 1921 and also, presented the idea of the day-fines system punishing rich and poor equally.