The O-Mor were a sentient race native to the planet Sachem II.

The O-Mor were the subject of a covert Starfleet cultural observation mission prior to the Dominion War. During that conflict, however, the planet was taken and occupied by Jem'Hadar troops. Following the war, in late 2376, a team from the USS da Vinci visited Sachem II to evaluate the level of cultural contamination left on the O-Mor people. The team determined that there was no harm done, owing to the O-Mor's easy-going nature.

Linguist Bart Faulwell also noted that the O-Mor language was the most boring he had ever encountered. (SCE eBook: Security)