Activists have been calling for the ban for decades. One campaigner was crushed to death under a lorry as she protested against the export of live calves for veal in 1995.
Britain's ruling Conservatives first proposed the ban in 2017 and touted it as a benefit of Brexit because European Union trade rules prevent member states from banning live exports to other countries in the bloc.
The Animal Welfare (Livestock Exports) Bill prohibits the export of cattle, goats, pigs and horses for slaughter, and fattening for slaughter.
It aims to improve animal welfare in farming by ending long, arduous journeys to other countries, during which livestock can suffer from overcrowding, exhaustion, dehydration and stress.
The UK parliament's unelected upper chamber, the House of Lords, passed the bill, meaning it will now head for royal assent before becoming law.
Emma Slawinski, director of policy, prevention and campaigns at the RSPCA animal charity, described it as "an extraordinary achievement" that activists had campaigned on for 50 years.
"Back in the 90s we had more than a million animals going out from the UK. It's an abhorrent trade. The suffering is intense and it goes on for a long time," she said.
"Some of those journeys were measured in days, not in hours, and they're never going to happen again."
The Compassion in World Farming animal welfare group called it a "truly momentous day" for farmed animals.
Britain saw huge protests against the export of livestock in the mid 1990s, including in the southeast coastal town of Brightlingsea in Essex, which UK media dubbed "The Battle of Brightlingsea".
On February 1, 1995, Jill Phipps was one of a few dozen animal rights activists who broke through a police line at Coventry Airport in central England.
She suffered fatal injuries when she became trapped under the lorry's wheels.
