The story was conceived by Robert Rodriguez's then seven-year-old son Racer Rodriguez, who receives an on-screen "Story By" credit.
While Max is on the dock before he runs into Sharkboy you can see a fast food bag for "Big Kahuna Burgers" a fictional burger joint used in a lot of Robert Rodriguez's films as well as those of his buddy Quentin Tarantino.
The character of "Max" is named after the middle name of Racer Rodriguez.
The movie was shot and completed so quickly that by the time Robert Rodriguez was ready to ship it, the advertisements weren't finished.
The face of the boy from the Troublemaker Studios logo can be seen as a design or sticker on the cover of Linus' binder in multiple scenes.