They're rather similar and there's a chance there are more ranks and titles between them, but these are the most official listings I could find.

The Old Republic Encyclopedia gives a list of ranks for the Republic and Imperial Armed Forces. I'll work to make corrections in a future post. If there are any discrepancies or errors, I apologize in advance. I based the ranks on the current usage of the US and UK Military ranking, as recognized by NATO. 1st SergeantĮ7 Chief Petty Officer - Sergeant 1st ClassĮ5 Petty Officer 2nd Class - Technical Sergeant MajorĮ8 Senior Chief Petty Officer - Master Sgt. (* - Imperials pronounce this as 'Leftenant')ĮNLISTED/NON-COMM OFFICER RANKS of the Galactic Republic & Sith EmpireĮ9 Master Chief Petty Officer - Sergeant Major / Command Sgt. O1 Sublieutenant / Lieutenant 2nd Class -đst Lieutenant* / Lieutenant*Įnsign / Ensign -Ēnd Lieutenant* / Lieutenant* 2nd Class O2 Lieutenant / Lieutenant -Ĝaptain / Captain O6 Commodore / Commodore -ěrigadier General O10 Fleet Admiral / Moff/Grand Moff -ğield Marshall / Moff/Grand Moff

Rank/Class Lvl Republic Navy / Imperial Navy - Republic Army/Marines / Imperial Army/Marines

OFFICER RANKS of the Galactic Republic & Sith Empire I did figure this would be a good suggestion for the Devs to help flesh out anything they may have in the works, as well as help any player who's RPing as either a Trooper or Agent. NOTE! These are just speculation and in no way is it meant that BioWare/EA has set these as the actual ranks in the game. In the end, I came up with a listing of ranks for both factions that seems to fit within the few bits of data the game has given us. Since the game seems to be generalizing and somewhat vague about the ranks of both enlisted and officers within the Republic and Imperial military chain-of-command, I did a bit of speculation and research.

Star wars imperial ranking system