StarQuest Online is a massively multiplayer online role playing game taking place in a large universe. It was created by Castle Thorn Software LLC.

There are over 17,000 star systems in StarQuest Online, and approximately 100,000 individual planets. Star positions were taken from Hipparcos satellite data for positional accuracy. Each planet was then created using a stellar dust accretion program based on the mass of each star. There are over 150 non-player character (NPC) races, and many other alien creatures inhabiting these worlds. Players can choose from three unique races when creating their characters, with more forthcoming. Several different classes of starships are available for players to command, explore, and battle with.

In StarQuest Online, players can assume the persona of a character living, exploring, fighting, and possibly dying in the 23rd century. As a loyal fleet officer, roving pirate, devious smuggler, deadly bounty hunter, wealthy merchant or ordinary civilian, players shape this world and its history into whatever they wish. StarQuest Online went live on September 21st, 2007 after more than two years of beta testing. After a free thirty-day trial period, players are required to pay a fee of $9.99 per month.

StarQuest Online is one of the few MMORPGs where players truly affect the outcome of the game. Players are fully able to command ships, set up colonies, and do anything else to affect player environments. There are no pre-programmed game environments, and no instance dungeons. Therefore, actions, victories, or colonies set up by players will remain, and affect game outcomes. StarQuest Online is currently the only space-based MMORPG where individual players can work together as crewmen on the same vessel, operating different control stations on the bridge. It has been announced that in Star Trek Online, each player will be a captain of their own ship, so that game will not have that capability.

There are very few non-player individual characters. All action and events occur mainly between player characters. However, some empires are entirely non-player characters. Administrators provide some scripted missions. However, players are fully able to create their own organizations, colonies and other structures within the game. The main organization within the games is the United Systems Alliance, which is the official "player" organization. Players may choose to create characters which are independent of the Alliance, but several alien empires are fully controlled by non-player characters. there are several playable races though. Starships require several players to function. Almost all starships have a real-world schedule to function, and cannot be used at all without at least one of the players present who serves as a senior officer in the game.