More than three quarters (77%) of the Society of Motor Manufacturers and Traders (SMMT) member companies said remaining in Europe would be the best for their business.
Only a minority 9% of the firms surveyed – which included car and commercial vehicle manufacturers, parts suppliers, aftermarket companies- said leaving would be best.
The survey was conducted before the start of the campaigning period.
The UK automotive industry is a huge employer, supporting 800,000 jobs across the UK and contributing £15.5 billion annually to the economy.
The industry is export- led with around 80% of vehicles heading abroad and over half of those (57.5%) destined for the rest of the EU.
"Unrestricted access to the world’s largest single market, the negotiating strength of the EU to secure international trade deals, the ability to shape technical regulations and free movement of labour all provide significant benefits to UK businesses. This is why SMMT member companies large and small are overwhelmingly in favour of remaining in the EU," the SMMT wrote.
Mike Hawes, SMMT chief executive, said: "UK Automotive is globally competitive, securing record levels of investment, creating tens of thousands of jobs annually and exporting to over 100 countries. We want this success to continue rather than jeopardise it by increasing costs, making our trading relationships uncertain and creating new barriers to our single biggest and most important market, Europe. Remaining will allow the UK to retain the influence on which the unique and successful UK automotive sector depends."
Senior figures from a wide range of UK-based automotive companies have reinforced this message.
Ken Gregor, chief financial officer of Jaguar Land Rover, said: "Remaining in the EU – our largest market – will increase Jaguar Land Rover’s chances to grow, create jobs and attract investment in future technologies. Our European supply chain has been fundamental in helping us to meet customer expectations worldwide and achieve sustainable, profitable growth."
Tony Walker, deputy managing director, Toyota Motor Manufacturing UK, said: "After considered review, we believe that continued membership of the European Union is best for our business and for our competitiveness in the longer term."
Dr Ian Robertson, member of the board of management, BMW AG,said: "We firmly believe Britain would be better off if it remained an active and influential member of the EU, shaping European regulations which will continue to impact the UK whatever the decision on Thursday."
Rory Harvey, managing director and chairman of Vauxhall, said: "We are part of a fully integrated European company where we benefit from the free movement of goods and people. We believe not to be part of the EU would be undesirable for our business and the sector as a whole."
John Leech, head of automotive at KPMG in the UK, also highlighted concerns from UK automotive market in the event of Brexit. He said: "Our report with the SMMT shows just how important the EU is to the UK automotive market – the UK automotive sector would likely lose sales, face slower supply chains and higher costs in the event of a Brexit. Given the low levels of profitability that accrue to mass market vehicle manufacture this would likely, over time, to lead to the loss of jobs overall. Even for the UK’s successful premium car manufacturers the loss of influence over EU regulation would come to damage their businesses over time.
"The automotive businesses we spoke to believe that the EU as an important bargaining force in global trade negotiations. Moreover, research and development, which is vital to the UK’s ability to be at the forefront of innovation in car manufacturing, is both heavily funded by the EU and requires access to the expertise and free movement of skilled engineers within the EU.
"While our report outlines the importance of EU membership to the UK automotive industry, it also poses some challenges to the sector. There is a clear demand for consistent application of regulation and reduced red tape."