At the time when William and Mary came to the English Throne, the majority of weapons were imported from Holland. They wanted to end England’s reliance on other countries and produce their own weapons. In 1689 the Government placed trial orders with five leading gunsmiths in Birmingham to supply 200 muskets a month at 17 shillings (85p) each. By 1692 these led to a definite contract that was to remain virtually unchanged for 150 years. The gunsmiths, now 14 in number, formed themselves into an association called "Birmingham Small Arms Trade" leading to the formation in 1861 of the Birmingham Small Arms Company. Arms manufacture continued until 1879 when a drop in sales caused the company to try other sources of income. They made parts, and complete machines, for the early bicycle industry until again concentrating on arms in 1892 although bicycle parts were still produced. About this time their trademark of three rifles was adopted.

Manufacture of complete bicycles was resumed in 1908 followed the next year by their first motorcycle. The first prototype motorcar was built in 1907 and a stand taken at the 1908 Olympia Show and approximately 150 cars were sold.

The BSA Board were so impressed with the 40hp Italia that had won the 1908 Peking-Paris race that they had a chassis bought for testing and produced a replica, the BSA-Italia. This car had a chassis, which weighed 28cwt (1420kg) on to which heavy landaulet or limousine bodies were fitted. These replicas and its successors had limited sales, but the board wanted a bigger share of the motor market. BSA negotiated to buy Daimler and the deal was announced in The Times of 2nd September 1910.

The amalgamation allowed the Daimler name to continue although the Daimler Company was wound up. BSA who closed their Montgomery Street factory in Birmingham and transferred all production to Daimler's premises held all the shares in the new company. BSA now had access to the Daimler Knight sleeve-valve engines.

Production ceased during hostilities until 1921 when a Hotchkiss powered model appeared which sold well until 1924 when the advent of the Austin Seven effected sales.

BSA acquired Lanchester in 1931 and built the Light 6 until 1936.

In 1933 the motorcycle branch of the company produced three-wheelers and other light front-wheel drive cars.

BSA chief Edward Turner considered several schemes to utilise the company's 250cc engine, one of which was a three-wheel car. Designed at the Meriden works of BSA's Triumph subsidiary and built by Carbodies Ltd (another BSA company), the resulting prototype was the Ladybird. Expected to cost £285 (UK Pounds) the Ladybird was a simple open two seat steel bodied car with a single rear wheel and handlebar steering. The car was cannibalised for parts while still at BSA before being restored in the USA by a micro car enthusiast. It is now in the UK in as new condition. The second prototype had a removable hard top and a steering wheel. Its whereabouts are unknown, although a rumour suggested it might be in Folkestone, Kent. The Ladybird project was abandoned around 1960.