Sigma Iotia was a star system located in Federation space near the Klingon and Romulan Neutral Zones, in the Beta Quadrant. It was 100 light-years from Canopus (Decipher RPG module: Worlds).

The star Sigma Iotia was either a large yellow star with a brightness of absolute magnitude +3 (ST references: Star Trek Maps, The Worlds of the Federation), or a Type KV main-sequence orange (Decipher RPG module: Worlds).

The system was home to nine planets. The second, Sigma Iotia II, or Iotia, was the only one capable of supporting life. Its inhabitants were the Iotians (ST references: Star Trek Maps, The Worlds of the Federation).

In the 2270s, the system had class 0 facilities for starship support (ST reference: Star Trek Maps).