Park Mun-su or Bak Munsu (Hangul: 박문수 , Hanja: 朴文秀) (born 1691-died 1756) was a Korean government official in the period of King Yeongjo of Joseon in the Joseon Dynasty in the history of Korea. He was famous for his lifetime spent protecting the Korean people from corrupt royal officials. Mun-su passed the state examination in 1723 and later became a secret royal inspector, or Amhaengeosa (暗行御史, 암행어사). He is the most famous Amhaengeosa in Korean history, and has become something of a legendary figure, and there are many legends surrounding his achievements as an Amhaengeosa. Two portraits of Park Mun-su have been preserved and are in good condition.