The company, which is the UK’s largest motoring manufacturer in terms of output, said new tariffs could hurt sales, jobs and the wider supply chain.
JLR’s strategy director Hanno Kirner made the comments at an event held at the Eiffel Tower ahead of the 2016 Paris Motor Show, due to get under way on October 1.
It comes after figures released by industry trade group the Society of Motor Manufacturers and Traders (SMMT) showed that demand for British-built cars is soaring overseas.
In the most recent data, car production for foreign markets shot up by 10.2% last month to hit 81,200, while cars made the domestic market rose 6.2% to 27,804.
There are fears from many observers that Brexit could hamstring the UK’s flourishing car industry and leave many factories struggling to attract investment.
Mr Kirner said that sales of Jaguars to EU countries went up twofold last year, with sales of Land Rovers jumping by 20%.
Tariffs could make it harder for JLR to sell its vehicles in the EU and buy from suppliers based there.
Currently, some 40% of the company’s purchasing budget is spent in Europe, he said.
In addition, restrictions on the free movement of people put in place after the UK leaves the EU could lead to problems recruiting workers with the right skills.
It is thought that a shortage of skills in the UK’s talent pool makes it essential for carmakers to hire from overseas.
Mike Hawes, chief executive of the SMMT, backed up Mr Kirner’s comments.
“We’re very concerned that the future state of the automotive industry and the success could be jeopardised if we’re not in the single market,” he said.
The event in Paris saw eight of the UK’s most influential car brands come together to promote the strengths of the UK automotive sector.
Senior executives from Aston Martin, BMW MINI, Honda, Jaguar Land Rover, Nissan, McLaren, Toyota and Vauxhall were joined by the British Parliamentary Under Secretary of State at the Department for International Trade, Mark Garnier.
Competitive business conditions, tariff-free trading and large-scale investment in new models and facilities have led to huge growth in the UK automotive industry in the past few years, and it is hoped that this continues.