The 17-year-old sister of actress Lindsay Lohan secured the deal with the agency early this week, reports JustJared.
NEXT Los Angeles Director Alexis Borges said in a statement: "We are very excited to be representing Aliana Lohan.
"She represents the future face of fashion and will be a photographer's dream with her chameleon-like beauty."
Ali previously modelled for Lindsay's 6126 fashion label in the line's Spring/Summer 2011 collection.
She made her acting debut in 2008's Mostly Ghostly and also starred in the reality series Living Lohan with mother Dina.
Lindsay has previously said that Ali has learned from the mistakes she has made and will not follow in her older sister's footsteps.