An Underdeveloped planet is a planet with a level of technology low enough to entitle it to protection under the Underdeveloped Planet Preservation Pact (UP3).

The UP3 defines three planetary classifications: underdeveloped planet, monitored planet, and developed planet. A monitored planet is one where contact is only allowed with a number of representatives of that planet's civilization, and an underdeveloped planet is one where no contact with that planet's civilization is allowed whatsoever. Emergency situations where lives are at stake are an exception to this rule, however, and secondary contact (contact where natives are not made aware of the fact that someone from a developed planet is present) is allowed.