Second Lieutenant is a junior Commissioned officer rank of the UNSC Marine Corps, UNSC Army, and UNSC Air Force. It is the lowest commissioned officer rank, and is equal in rank to Ensign in the UNSC Navy. They are given command of platoons, such as the case of Second Lieutenant Oros in Halo: The Flood.
In informal settings, Second Lieutenants are referred to simply as "Lieutenant".
|UNSC Defense Force commissioned officer ranks|
|O-1||O-2||O-3||O-4||O-5||O-6||O-7||O-8||O-9||O-10||Special (Wartime Only)|
|Air Force:||2nd Lt||1st Lt||Capt||Maj||Lt Col||Col||Brig Gen||Maj Gen||Lt Gen||Gen||GOAF|
Second lieutenant is the lowest officer rank used by the MACOs and Federation Marines, superior to enlisted grades and subordinate to first lieutenant and captain (marines). A second lieutenant commands a platoon, about 30 troops.
This rank is also used in the Bajoran Militia and other armies. (DS9)
|Bajoran Militia||Tal Shiar||Federation
|Enlisted personnel||Non-commissioned officers||Etc||Officers||Flag officers|
|Bajoran Militia||(unknown)||2nd Lt||1st Lt||Capt||Maj||FCol||Col||BGen||MajGen||LtGen||Gen|
|Ground troops||Bekk||Cpl||Sgt||MSgt||SgtMaj||2nd Lt||1st Lt||Capt
|Romulan ranks||Ground forces||Trooper||Sergeant||SubLt||Lt||Capt||Maj||Cent
|Romulan Star Navy||Uhlan||Petty officer||Cent||SCdr||Cdr||Cgen||Adm (Ar'nal)|
|Tal Shiar||2nd Lt||1st Lt||Capt||Maj||Col||General|
|WO||2nd Lt||1st Lt||Capt||Maj||LtCol||Col||BGen||MajGen||LtGen||Gen||GenCorps|