Whenever Paul Rudd appeared on Late Night with Conan O'Brien (1993), he likes to show a clip from his newest film, and inevitably shows a clip of Eric rolling off a cliff and falls into the water. Jennifer Aniston, who made her feature film debut in this movie, went on to costar with Rudd in many projects, including The Object of My Affection (1998), Wanderlust (2012), and Friends (1994). Rudd's been doing this joke for many years, even when promoting his film Ant-Man (2015).

Jade Calegory has spina bifida, and uses a wheelchair in real life.

The McDonald's scenes were all shot in City of Industry, CA, just outside Los Angeles. The set was a real-life McDonald's built specifically for crew member training and television commercials. Everything inside worked, but it never served a real customer. When it wasn't being used, it was locked up behind a chain link fence. It was torn down and rebuilt in 2006.

Part of the film's box-office intake was donated to the Ronald McDonald House Charities.

This film ends with a freeze frame and the superimposed title "We'll be back!" It was such a dismal box office failure that the proposed sequel was never made.

Coca Cola and McDonalds backed the movie, thus the numerous references to both of those products.

Listed among The 100 Most Amusingly Bad Movies Ever Made in Golden Raspberry Award founder John Wilson's "The Official Razzie® Movie Guide".

M.A.C. is an acronym for Mysterious Alien Creature.

Kim Basinger and Anjelica Huston were each offered the female lead role. Both declined.

In a review in the Washington Post, Richard Harrington wrote "In fact, "MAC and Me" could just as well have been called "O.T. - The Other Terrestrial," so frequent and clumsy are its references to "E.T." Forget about calling home; E.T., call lawyer".

It is often questioned why Eric has a bear costume ready to go when he has to sneak Mac into the birthday party; this can be explained when Eric and his family first move into the house: Eric is seen in his room unpacking boxes. If one looks closely, there is a teddy bear sitting inside a box with features identical to those of Mac's costume. This would indicate that Eric took the stuffing out of the teddy bear, thus turning it into a costume for Mac.

Jennifer Aniston made her debut in this movie as an uncredited extra. She can be seen sitting on a curb, watching the dancers in the McDonald's parking lot.

The scenes of MAC running from the backyard into the hills were filmed in Hacienda Heights, California.

This the second of three movies with George 'Buck' Flower about alien visitation. The others were Starman (1984) and They Live (1988).

Jonathan Ward voiced Zak in FernGully: The Last Rainforest (1992), also scored by Alan Silvestri.

"Mac" was the nickname of McDonald's Co-Founder Maurice McDonald.

At the end, MAC's father drives a 1957 Cadillac Series 62 Convertible.

The Cruise family van is a 1987 Volkswagen Vanagon GL Wolfsburg Edition.

According to "How McDonald's Bizarre 'ET' Knockoff Got Made," the scene of Eric rolling down the hill, falling off a cliff into the water below was filmed at Malibu State Creek Park, California, Somehow the scenery of the creek park was merged with the Cruises' backyard in Calabasas.