Trivia

According to a September 1972 "Los Angeles Times" news item, the rat portraying Ben won a PATSY Award, which honors animal actors.

According to studio publicity notes, Moe Di Sesso, who trained the 500 rats used in Willard (1971), trained approximately 4,000 rats for this film. The film's pressbook implied that there would be a second sequel featuring 10,000 rats to be released in 1973, but it was never made.

According to Michael Jackson, his theme song for this film, which was also titled "Ben" and which played during its final scene and its closing credits, was one of his favorite songs. It was written for the film by lyricist Don Black and composer Walter Scharf. It was also the title track on Jackson's second solo album, which was released just before his 14th birthday, and became a #1 hit on the Billboard pop charts - a first for Jackson as a solo artist.

Although the film Willard (1971) was based on the novel "Ratman's Notebooks" by Stephen Gilbert, this sequel to it only uses the character of Ben the rat and has a new story and an original screenplay that were both written by Gilbert Ralston, who also wrote the screenplay for the previous film.

Donny Osmond, then a popular teen idol, said that the theme song was offered to him first, but his schedule prevented him from recording it and the song was then given to Michael Jackson instead.