Mystery Writers of Japan (Japanese: 日本推理作家協会, Hepburn: Nihon Suiri Sakka Kyōkai) is an organization for mystery writers in Japan.
It also presents the Edogawa Rampo Prize to amateur writers who has had few or no novels published commercially.
On 21 June 1947, Edogawa Rampo founded the Detective Fiction Writers Club (探偵作家クラブ, Tantei Sakka Kurabu), which was based in Tokyo.
In 1954, the Club merged with the Detective Fiction Writers Club of Kansai (関西探偵作家クラブ, Kansai Tantei Sakka Kurabu), the counterpart based in Kansai region, and changed its name to the Detective Fiction Writers Club of Japan (日本探偵作家クラブ, Nihon Tantei Sakka Kurabu).
On 31 January 1963, the club changed its name to Mystery Writers of Japan (日本推理作家協会, Nihon Suiri Sakka Kyōkai).