Some 180,168 cars were registered last month, the Society of Motor Manufacturers and Traders (SMMT) said.
Growth was driven by the fleet sector, which saw a 4.2% rise. Private registrations fell by 1.1%.
Some 2.33 million cars have been registered in 2016 so far, up 2.5% on the same period last year.
SMMT chief executive Mike Hawes said: "September's number plate change is always a hard act to follow so the market's growth in October, albeit moderate, is welcome news.
"Low interest rates, affordable finance packages and a range of exciting new models helped attract buyers into showrooms and we now look to Government to ensure consumer and business confidence remains buoyant."
Petrol demand rose by 4.9% last month, while diesel registrations fell by 2.4%.
Alternatively-fuelled vehicles saw growth of 12.4%.