1901 - 1914 In the beginning
Sir John Wolfe-Barry - the man who designed London’s Tower Bridge - instigated the Council of the Institution of Civil Engineers to form a committee to consider standardizing iron and steel sections on January 22, 1901.
Subsequently, on April 26, 1901, the first meeting of the Engineering Standards Committee took place. As a result, the variety of sizes of structural steel sections was reduced from 175 to 113 and standardization was underway.
In 1903 the need to indicate to buyers that goods were 'up to standard' led to the creation and registration of the British Standard Mark - to become known later as the Kitemark® when applied to tramway rails the number of gauges was reduced from 75 to 5.
1914 – 1945 Standardization grows
In World War I, British Standards were used by the Admiralty, the War 
Office, the Boad of Trade, Lloyd's Register, the Home Office, the Road Board, the London County Council and many then colonial governments.
During the 1920s standardization spread to Canada, Australia, South Africa and New Zealand. Interest was also developing in the USA and Germany.
On April 22, 1929, the Engineering Standards Committee, (since 1918 the British Engineering Standards Association) was granted a Royal Charter. A supplemental Charter was granted in 1931 changing the name, finally, to The British Standards Institution.
When World War II broke out, ordinary standards work was stopped and efforts were concentrated on producing 'war emergency standards', with the British Government officially recognizing BSI as the sole organization for issuing national standards in 1942.
Between 1939 and 1945 over 400 war emergency standards were produced.
1946 – 1975 International consolidation and consumer concerns
1946 saw the first ever Commonwealth Standards Conference, held in London and organized by BSI, which led to the establishment of the International Organization for Standardization (ISO).
By the late 1950s and 1960s the market place was flooded with consumer goods, many of dubious quality. As a result, 1953 saw the Kitemark® applied to domestic furniture, pressure cookers and motorcycle helmets to help consumers know whether goods were well produced.
Standards were also published for subjects such as checking air pollution, nuclear energy, safety colors for use in industry, schools and office furniture and the carrying of live animals by air.
The Women’s Advisory Committee was formed in 1951 to advise on standards affecting the domestic consumer. It was the precursor of today’s Consumer Policy Committee which coordinates consumer representation on all BSI’s technical committees for consumer products.
1959 saw the opening of the Test House at Hemel Hempstead to test equipment for export to Canada, the beginning of BSI Product Services. Government regulations also introduced the compulsory application of the Kitemark® for car seat belts and motorcycle helmets which was conducted at Hemel Hempstead.
1975 - 1997 Management Systems Standards 
The world's first management systems quality standard, BS 5750, was published by BSI in 1979. In 1987, it was superseded by the ISO 9000 series of international standards which BS 5750 inspired.
Revised in 1994 and then in 2000, the international quality management systems standard has proved a global success with more than 776,000 ISO 9001 certificates issued in 161 countries and economies by the end of 2005.
Following in the successful footsteps of BS 5750, BSI published the world’s first standard for environmental management systems, BS 7750, in 1992.
Its international successor, ISO 14001 was published in 1996. In the ten years since its introduction the standard has been rapidly adopted by business – up to the end of 2005 more than 111,000 ISO 14001 certificates (1996 and 2004 versions consolidated) had been issued in 138 countries and economies.
BSI Group also began its international expansion, establishing BSI Americas in Reston, Virginia in 1991 and establishing its first Asian office in Hong Kong in 1995.
Since 1998 
BSI goes global In 1998, after changes to the Royal Charter, BSI Group acquired:
- CEEM, a leading American management system training and publication services provider, and
- International Standards Certification Pte Ltd, a Singapore based certification organization.
In January 2002, KPMG's ISO registration business in North America was acquired, making BSI Group the largest registration body in North America.
In 2003, BSI acquired 100 percent of BSI Pacific Ltd, in order to consolidate the Group's penetration of the immense Greater China certification market.
BSI also acquired a 49 percent shareholding in British Standards Publishing Limited (BSPL) realizing a new sales, distribution and licensing agreement to expand the Group's ability to deliver standards to a wide range of industrial and commercial markets within the UK and worldwide.
In 2003, BSI also celebrated the Kitemark®'s centenary and becoming a business-to-business Superbrand. 
In 2004, the Group acquired KPMG’s certification business in Holland – KPMG Certification B.V. – to provide an enhanced range of services to businesses across the Benelux region and the rest of continental Europe.
In 2006, BSI acquired:
- German certification business NIS ZERT;
- Entropy International Ltd, one of the world's leading providers of performance and sustainability software solutions
- Benchmark Certification Pty Ltd, Australia's second largest certification body and the business of Greenall Barnard Associates Ltd trading as ASI-QS, a UK based company which specializes in Six Sigma training and implementation
As a result of these strategic moves, and through more than a century of growth, BSI Group now delivers a comprehensive business services portfolio to clients, helping them raise their performance and enhance their competitiveness world-wide.
