The 21-year-old east Londoner scored seven goals in 41 appearances on loan at Hull City last season, helping them to promotion to the Premier League.
But he has only played once for Arsenal this term, a 4-0 win over Nottingham Forest in the EFL Cup in September.
"We fought off competition from other clubs to sign Chuba," said boss Chris Hughton, whose side top the table.
"He is a young talent who gained valuable experience with Hull in the Championship last season, will give us really good pace in the forward areas and complement the other strikers at the club."
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Championship promotion-chasers Brighton have signed Arsenal striker Chuba Akpom on loan until the end of the campaign.