Linn Markley Farrish (October 3, 1901 – September 11, 1944) was an American rugby union player and alleged spy.

While acting as the OSS liaison officer to Josip Tito's Yugoslav Partisans, as part of Maclean Mission (Macmis), he submitted an assessment of anti-Nazi resistance.

Farrish is referenced in the following Venona project decryption: 1397 KGB New York to Moscow, 4 October 1944.

[4] Biographer Mark Ryan states "Patriotic Farrish would never do anything to harm his beloved USA.

"[5] Fitzroy Maclean jocularly referred to him in his memoir Eastern Approaches as "my American chief of staff".