The Self-Determination Movement party used three tear gas canisters in the Assembly building as the vote was due to start on Wednesday, forcing all politicians to leave the hall.
The 120-seat parliament was expected to vote with the two-thirds needed to ratify the 2015 agreement.
The Movement party claims the deal would see Kosovo lose 20,000 acres of its territory to its neighbour, though experts dispute this.
US ambassador to Kosovo, Greg Delawie, condemned the "violence" as a "political tool" with "no place" in the country.
"I urge MPs to reconvene and finish the vote today," he added.
Nataliya Apostolova, the European Union's ambassador, said on Twitter: "Appalled by tear gas release in Kosovo Assembly! Shocked that members of a parliament in Europe are resorting to dangerous tactics pulling Kosovo backwards.
"[I] call on all MPs and all parties to go back to [the] Assembly to defeat such unacceptable practices that go against democratic society and the future of the Kosovo people. MPs, vote for the future, not for the past!"
The proposed land deal is a precondition set by the EU in order to give Kosovans the ability to travel freely inside the visa-free Schengen area. Montenegro has already approved the deal.
Kosovo declared independence from Serbia in 2008 - though this is not recognised by Belgrade - and hopes to qualify for EU membership in the future.
In 2016, Kosovo signed the Stabilisation and Association Agreement with the EU, a deal that will see Balkan nation aim to gradually integrate its policies in line with Europe's 28-member union.
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies