Steve Carell said that this movie may be his last as the voice of Gru. However, Carell stated that if he was asked to do a cameo in any future Minion sequels, he happily would. In Minions: The Rise of Gru (2022), Carell was confirmed to reprise his role as Gru. Plus, he came back to voice Gru in Despicable Me 4 (2024).
Trey Parker stated that his daughter was a key factor in his decision to take the role of Balthazar Bratt. He said that she was almost two at the time and he thought it would be cool for her to "actually watch something I've done." Parker is best know as co-Creator of South Park (1997), with partner Matt Stone. When asked in an interview how old his daughter had to be to watch South Park, Parker jokingly responded that she had to be 36 years old.
Agnes' voice actress Elsie Fisher from the first and second movies was replaced by Nhev Scharrel, due to Fisher getting too old for the role.
When the giant Balthazar Bratt robot is attacking Hollywood, K.I.T.T. from Knight Rider (1982) can be seen backing away.
The country in which Dru lives and from which Gru originates is the fictional European country of Freedonia. This is the same name as a similar fictional European country in the The Marx Brothers movie Duck Soup (1933). The name of the diamond Bratt tries to steal is the Dumont Diamond, named after Margaret Dumont, who played the recurring "straight man" character in a great many Marx Brothers movies, including Duck Soup.