The Adventures of Jo, Zette and Jocko is a Franco-Belgian comics series created by Hergé, the writer-artist best known for The Adventures of Tintin. The heroes of the series are two young children, brother and sister Jo and Zette Legrand, and their pet chimpanzee Jocko, plus their parents, Mr Legrand, Jo and Zette’s father, aerospace engineer and designer, and Mrs Legrand, Jo and Zette’s mother, housewife and Mr Legrand’s wife.

Jo, Zette and Jocko appear on the rear covers of some The Adventures of Tintin comic books, but never appear in the stories. A few Jo, Zette and Jocko comics allude to characters or events in The Adventures of Tintin, such as the Maharaja of Gopal (briefly mentioned in The Castafiore Emerald) appearing as a prominent character, and a portrait of Captain Haddock in the Legrand house.^{[citation needed]}

The following are the five Jo, Zette and Jocko titles, both in English and French, which are published between 1951 and 1957.

No.	English title	French title	Notes	Published
1	The 'Manitoba' No Reply	Le "Manitoba" ne répond plus	Volume 1 of The Secret Ray	1952
The transatlantic liner Manitoba breaks down on its way to England and then the passengers and crew fall strangely asleep. When they wake up it is to find that they have all been robbed of their valuables. Later, while on holiday at the seaside, Jo, Zette and Jocko, playing in a rowing boat, get lost at sea when a thick fog comes down. Rescued by a submarine, they are taken to a secret undersea base where a mad scientist has plans for the two young children.
2	The Eruption of Karamako	L'Eruption du Karamako	Volume 2 of The Secret Ray	1952
Jo, Zette and Jocko escape the undersea base in an amphibious tank, and end up on an island. But their problems are far from over. They have to deal with cannibals, modern-day pirates, an erupting volcano, gangsters, the media and there is still the mad scientist who wants them for his evil plans.