The actress' star father Anil Kapoor has also thanked the minister for the "immense support".
"Neerja" is a biopic on the life of air hostess Neerja Bhanot who sacrificed her life while saving passengers on board Pan Am Flight 73, which was hijacked in Pakistan.
"A huge thank you to honourable CM Vasundhara for making 'Neerja' tax free. Humbled by the gesture towards our nation's pride Neerja Bhanot," Sonam tweeted on Friday.
The Ram Madhvani directorial, produced by Fox Star Studios and Bling Unplugged, features Sonam and Shabana Azmi in pivotal roles.
"The immense support given to 'Neerja' shows how she has inspired millions! Thank you honourable CM Vasundhara...," the actor-producer tweeted.
"Neerja", which released on February 19, was also declared tax-free by the Maharashtra and Chhattisgarh governments.
