Anachronisms: The car burned in the Calcutta riot scenes (some time between 1946 and 1948) is an Ambassador, an Indian-made copy of a 1954 Morris Oxford.
Continuity: When Gandhi is escorted into the office of the top prison official, the pendulum on the grandfather clock in the background jumps between shots.
Factual errors: In the scene where the Pakistani flag is being raised for the first time, the anthem that is playing is the current national anthem of Pakistan ("Qaumi Tarana"). The original national anthem of Pakistan was a different song (written by a Hindu), which was written days prior to the ceremony and only lasted 18 months as Pakistan's anthem.
Miscellaneous: In the opening scene in South Africa, Gandhi is riding first class on a steam locomotive. The first class car is shown as the forward car, closest to the engine. In passenger steam engines, first class would be the rearmost car, farthest away from the engine's heat and exhaust. Second or third class would be nearest the engine.
Revealing mistakes: In the massacre scene Gen. Dyer is pacing back and forth between the two rows of firing soldiers. Right before the cut to the crowd he steps in front of a standing soldier firing.
Incorrectly regarded as goofs: While it is true that electricity was unavailable to most Indian villages during Gandhi's lifetime, it can be expected that poles supporting what seem to be power lines along the railroad right-of-way during Gandhi's tour of India are instead supporting telegraph lines, some of which were in place as early as the 1850s.
Factual errors: In the movie, The South African police were shown both arresting and beating Gandhi for burning passes during his protest of the Pass Law. Although Gandhi and his fellow protesters were arrested for burning the passes, in reality neither Gandhi or any of the protesters were ever beaten by the police during the protest.
Factual errors: Gandhi is shown to have two sons and a daughter. In reality Gandhi only had sons.