People on the set were forbidden from uttering phrases from Carrey's past "silly" movies.

The motto on the double archway in the Seahaven town center is UNUS PRO OMNIBUS, OMNES PRO UNO: "One for all, all for one" in Latin, thus fitting the premise of the Truman Show.

In an early scene on Truman and Meryl's kitchen table is a bottle of vitamin D - needed for those without exposure to the (real) sun.

Director Peter Weir filmed in the 1.66:1 ratio to make it feel more like a television show.

There's a notable difference between the trailer and the final version of the movie. The change was made in the scene where the lamp falls down next to Truman. In the trailer, as Truman looks up, he sees a closing hole in the sky, but in the final version of the movie, this hole is replaced by a lamp post.