The lions "Boy," "Girl," and "Ugas" were freed upon the completion of production, under protest from the film company who wanted to sell the lions to zoos to recoup some of their money from filming.
A documentary follow-up to Born Free (1966), entitled The Lions Are Free (1969), was released. The film follows Born Free-actor Bill Travers as he journeys to a remote area in Kenya to visit George Adamson, and several of Adamson's lion friends in his lion rehabilitation reserve, Kora Reserve. It also tells what happened to the lions Boy, Girl, Ugas, Mara, Henrietta, and Little Elsa, and other lions that appeared in the first film.
The real-life George Adamson and Joy Adamson were not the blissful couple portrayed on screen, with Joy's rather headstrong and sometimes bullying attitude becoming such an annoyance that she was banned from the set.
The theme song was not heard on the original British release of the film, although it later won the Academy Award for Best Song.