Plots in Season 3 are based on stories from the Dexter's Laboratory comic book series by DC.
Blast you, Dexter! Now there's an idea... blast Dexter. Yes, blast Dexter!
In the episode where Dexter is learning piano, the professor says they'll start on C, but they clearly start on F.
After the credits of the 2001 season, Dexter and Dee-Dee are inside the Cartoon Network logo, Dee-Dee presses a button that makes Dexter explode.
The episode D & DD, an episode parodying the famous role-playing game Dungeons and Dragons, was changed to Sibling and Sorcery to avoid legal troubles.