As explained in the Wand of Wishing game, Petpets come from an alternate dimension know as Petaria. In this dimension, Petpets are capable of speaking, wearing clothes, and walking upright. There are entire Petpet-based societies in Petaria, with Petpet Park being one of the most well known. As seen during the Operation: Petpet Park event, Petpets can enter Neopia from Petaria via magical portals. Petpets who enter Neopia lose their ability to speak and start acting in a more animal-like manner.
On the Neopets website Petpets are class of items that can be attached to Neopets. Each Neopet can only have one Petpet attached to them at a time. Users can attach a Petpet to their Neopet by clicking on the desired Petpet in their inventory and then selecting the Give pet to... option from the resulting drop-down menu. Users can visit an attached Petpet by clicking on its picture on the Quick Reference page. Doing this will take the user to a page where they can rename their Petpet, talk to it, or remove it. This page also displays the Petpet's level and how many days it has been attached to its current Neopet.
There are many activities that users can do with their Petpets on the Neopets website. Users can fight their Petpets against computer controlled challengers in the game Petpet Battles. They can also use their Petpets to gather treasure by sending them into the Mysterious Symol Hole or the Grave Danger catacombs. Users can have their Petpets wake up the Turmaculus, or they can take their Petpets to the Petpet Lab Ray. Each user that has a Petpet is also qualified to win the Petpet Protection League award.
While most Petpets can be purchased from official Neopian shops, some of them can only be earned by participating in certain activities on the Neopets website. For example, there are some Petpets that can only be obtained by combining items at the Cooking Pot or at Tangor's Workshop. Other Petpets can only be obtained by using the Petpet Lab Ray. There are a handful of Petpets that are only available in Newbie Packs, and some Petpets are exclusive prizes given out during the various plots and events that happen around Neopia. Most Petpets are also tradable, meaning that they can be purchased from other users using the Auction House, Trading Post, or user shops.
- Main article: Colour
Since October 2, 2001, users have been able to change the colour of their Petpets. Users can change the colour of their Petpet by using an appropriate Paint Brush at the Petpet Puddle. Since Petpets are items, changing the colour of a Petpet changes it into a different item. For example, changing the colour of a Babaa to Blue will causes the affected Babaa item to become a Blue Babaa item. In order to change a coloured Petpet back into its original form, users have to change the colour of the Petpet back to the default colour of its species. For example, to change the aforementioned Blue Babaa item back into a Babaa item, the user would have to change to the colour of the Babaa back to White, which is the default colour for the Babaa species.
The Petpet Lab Ray can also change the colour of a Petpet; however, the Petpet will return to its original form when it is removed from its Neopet.
There are currently 15 different types of Petpet, each of which have a different theme:
||Altadorian Petpets are based off of creatures found in ancient Greek and Roman mythology.|
||Aquatic Petpets resemble various under-water creatures.|
||Desert Petpets tend to be desert or ancient Egyptian themed.|
||In general, Faerie Petpets are colorful and have some sort of wings.|
||Fanciful Fauna Petpets are based off of Asian creatures, both real and mythological.|
||Geraptiku Petpets are usually rainforest or Amazon themed. Many of them resemble real-life rainforest creatures.|
||Maraquan Petpets are ocean-themed Petpets, many of which resemble real-life sea creatures.|
||Medieval Petpets are generally fantasy or medieval-Europe themed.|
||Moltaran Petpets have fire/magma or rock associations. Many of the Petpets in the category can only be obtained by combining ingredients at Tangor's Workshop.|
||This was originally the only category of Petpet. As such, it has no specific theme.|
||Pirate Petpets are pirate and sailing themed.|
||Robot Petpets resemble either robots or outer space aliens. Many of the Petpets in the category can only be obtained by visiting Meteor Crash Site 725-XZ.|
||Spooky Petpets are usually Halloween or horror themed.|
||Tyrannian Petpets are prehistoric or dinosaur themed.|
||Wintery Petpets are generally Christmas or winter themed. They are sometimes given out by the Advent Calendar.|
- Main article: Petpet Park
Petpet Park was Neopet's sister site and a massively multiplayer online game that focused exclusively on Petpets. Petpet Park was launched during 2008, and it was discontinued and taken offline in 2014. In this game, user could create a Petpet avatar and then use it to explore the world of Petpet Park. In the park, users could play games, interact with other users, and earn park points to buy items. Other than being set in the same universe and using the same log-in, Petpet Park and Neopets were completely separate sites.
- Petpet Appreciation Day occurs every 8th June, and began in 2005.