MLAs spent several hours on Monday debating the measures, which formed part of a private member’s bill on human trafficking and exploitation.
Clause six of the bill makes it illegal for someone to obtain sexual services in exchange for payment.
Northern Ireland is the first part of the UK to vote in favour of the measure.
There is still some way to go before the bill becomes law, but the prospect of a ban on paying for sex in Northern Ireland has taken a significant step forward.
Supporters said the clause in Lord Morrow’s private member’s bill tackled a main driver for human trafficking.
Opponents included Justice Minister David Ford who claimed it would be difficult to enforce.