The Tale of the Giant Rat of Sumatra is the seventh comedy album produced by the Firesign Theatre and released in January 1974 by Columbia Records.

It is a Sherlock Holmes pastiche story loosely inspired by "The Adventure of the Sussex Vampire" by Arthur Conan Doyle.

A giant rat of Sumatra is briefly mentioned in a throw-away line in "The Adventure of the Sussex Vampire", a story in The Case-Book of Sherlock Holmes by Arthur Conan Doyle.

The lighthearted tale is full of puns, including a running gag in which Flotsam, eager to chronicle the adventure, tries to write down everything Stones says but mishears it all as something similar-sounding; for example, "rattan-festooned" is written down as "rat-infested."

In the liner notes to Shoes for Industry: The Best of the Firesign Theatre, David Ossman was cheerful when discussing it and said that "I always thought it was the closest thing to the relentlessly pun-filled one-acts we did in clubs.