▁States ▁Ar med ▁Forces , ▁the ▁term ▁junior ▁officer ▁is ▁used ▁by ▁the ▁Navy ▁and ▁the ▁Coast ▁Guard ▁for ▁officers ▁in ▁the ▁ranks ▁of ▁en sign ▁( O - 1 ), ▁lieutenant , ▁junior ▁grade ▁( O - 2 ), ▁lieutenant ▁( O - 3 ), and ▁lieutenant ▁commander ▁( O - 4 ). ▁ ▁The ▁U . S . ▁commission ed ▁officer ▁corps ▁is ▁divided ▁into ▁ten ▁pay ▁gr ades ▁( O - 1 ▁through ▁O - 1 0 ). ▁▁ ▁Offic ers ▁in ▁pay ▁gr ades ▁O - 1 ▁through ▁O - 3 ▁are ▁considered ▁company ▁grade ▁officers . ▁In ▁the ▁Army , ▁Marine ▁Corps ▁and ▁Air ▁Force , ▁these ▁pay ▁gr ades ▁correspond ▁to ▁the ▁ranks ▁of ▁second ▁lieutenant ▁( O - 1 ), ▁first ▁lieutenant ▁( O - 2 ), ▁and ▁captain ▁( O - 3 ), ▁and ▁in ▁the ▁Navy , ▁these ▁pay ▁gr ades ▁correspond ▁to ▁en sign ▁( O - 1 ), ▁lieutenant ▁( j un ior ▁grade ) ▁( O - 2 ), ▁and ▁lieutenant ▁( O - 3 ). ▁▁ ▁Offic ers ▁in ▁pay ▁gr ades ▁O - 4 ▁through ▁O - 6 ▁are ▁considered ▁field ▁grade ▁officers . ▁In ▁the ▁Army , ▁Marine ▁Corps , ▁and ▁Air ▁Force , ▁these ▁pay ▁gr ades ▁correspond ▁to ▁the ▁ranks ▁of ▁major ▁( O - 4 ), ▁lieutenant ▁colon el ▁( O - 5 ), ▁and ▁colon el ▁( O - 6 ), ▁and ▁in ▁the ▁Navy , ▁lieutenant ▁commander , ▁commander , ▁and ▁captain .