This was Burgess Meredith's last film. He died of complications of Alzheimer's disease on September 9, 1997. He showed symptoms at the time of this movie's filming, and had to be coached during each scene in which he appeared. Meredith's acting talents are evident despite his failing mental faculties.
The eighth pairing out of ten movies of comic actors and great friends Jack Lemmon and Walter Matthau.
Another sequel titled "Grumpiest Old Men" was planned. It was to be filmed in Rome and feature Marcello Mastroianni as Maria's former husband who contests her marriage to Max on the grounds that their divorce was never finalized. The film however was canceled due to Mastroianni's death in the following year and the box-office failures of Out to Sea (1997) and The Odd Couple II (1998).
There's one scene where Jack Lemmon has to sleep over at Walter Matthau's, and he has to deal with his extreme untidiness, much like their most famous movie, The Odd Couple (1968).
Max and John have for years been trying to catch a catfish they call "Catfish Hunter." It is named for Baseball Hall Of Fame pitcher Jim "Catfish" Hunter.