"As the movie revolves around boxer Mary Kom, the pride of the northeast and the country, we have decided to exempt it from entertainment tax," Chief Minister Tarun Gogoi said in a statement here.
Based on the life of the Olympic bronze medal winner and five-time world amateur boxing champion, the film is scheduled for release on September 5.
Assam is the third state to have made the film tax-free after Maharashtra and Uttar Pradesh.