McQueen, 20, came through Southampton's youth ranks and has played one first-team game - as a sub against Sunderland in the FA Cup in February 2014.
"As good as the under-21s is, you want to be pushing yourself and the next step for me was playing football," he told BBC Essex.
"I've got the opportunity here so I've got to take it as well as I can."
Find all the latest football transfers on our dedicated page.
League One side Southend have signed midfielder Sam McQueen on loan from Southampton for the rest of the season.