Lieutenant junior grade
The rank of lieutenant junior grade, sometimes abbreviated to lieutenant jg or junior lieutenant, was a junior officer grade used by Starfleet that was positioned between an ensign and a full lieutenant. 

During certain points in its history, Starfleet discontinued the rank of lieutenant junior grade, promoting ensigns directly to the full grade of lieutenant. This was the case in the mid 2270s, when ensigns adopted the sleeve insignia of the former lieutenant jg rank. ()

Benjamin Sisko once recalled the time he got promoted to lieutenant, stating that "It took me a while to get used to being called "sir" by my friends who were still ensigns." () 

In an alternate timeline created by Q, where Captain Jean-Luc Picard was given the chance to walk away from his fight with the Nausicaan that caused serious injury to his heart, which forced a bionic replacement to be installed, he returned to the present as a mere assistant astrophysics officer with the rank of lieutenant junior grade. It was later revealed by Q that it was that near-death experience that made the young Picard realize just how fragile life was and how important it could be, thus making him even more determined to make his mark in the universe and take risks, to earn his place as the captain of the . ()

After taking the liberty to speak with Starfleet Medical, Captain Benjamin Sisko got them to waive the rest of Ezri Dax's training and gave her a commission as a full counselor with the rank of lieutenant. ()

Lieutenants junior grade

Appendices

See also 
 Sublieutenant

Background information 
The rank of "lieutenant junior grade" was portrayed in nearly all Starfleet rank schemes, but was only mentioned in the dialogue of the  episode  and the  episode , while the term "junior lieutenant" appeared in dialogue in .

According to one early draft script of  (dated ), Lieutenant Ilia had been identified in dialogue as a "Lieutenant Junior Grade".

Lieutenant junior grade is never seen on the  or referenced in . A  article on the 2151 uniforms and rank did not mention lieutenant junior grade or lieutenant commander. ()

External link 
 

bg:Младши лейтенант
cs:Podporučík
de:Lieutenant Junior Grade
es:Teniente grado junior
fr:Sous-lieutenant
it:Tenente JG
ja:中尉
nl:Luitenant j.g.
sr:Млађи поручник
Military ranks