Lieutenant, Junior Grade
From Halopedia, the Halo wiki
Lieutenant, Junior Grade, abbreviated to LTJG, is a junior commissioned officer rank of O-2 in the United Nations Space Command Naval Command (NAVCOM) rank structure; including the UNSC Navy and Office of Naval Intelligence. It is preceded by Ensign, and subordinate to a Lieutenant.
Command of staff section.
- Halo: Official Spartan Field Manual - PART 8: UNSC ORGANISATION, NAVCOM Ranks, page 140-141