| B | Baron |
| b | born |
| BA | Bachelor of Arts; British Airways |
| BAA | British Airports Authority |
| BAAS | British Association for the Advancement of Science |
| BAC | British Aircraft Corporation |
| BACUP | British Association of Cancer United Patients |
| BAe | British Aerospace |
| BAFTA | British Academy of Film and Television Arts |
| BAG | Business Art Galleries |
| BAI | Baccalarius in Arte Ingeniaria (Bachelor of Engineering) |
| BAIE | British Association of Industrial Editors |
| BALPA | British Air Line Pilots' Association |
| BAO | Bachelor of Art of Obstetrics |
| BAOR | British Army of the Rhine (formerly on the Rhine) |
| bapt | baptised |
| BARC | British Automobile Racing Club |
| BArch | Bachelor of Architecture |
| BAS | Bachelor in Agricultural Science |
| BASc | Bachelor of Applied Science |
| BBB of C | British Boxing Board of Control |
| BBC | British Broadcasting Corporation |
| BBS | Bachelor of Business Studies |
| BC | Before Christ; British Columbia; Borough Council |
| BCE | Bachelor of Civil Engineering; Before the Christian Era |
| BCh | Bachelor of Surgery |
| BChir | Bachelor of Surgery |
| BCL | Bachelor of Civil Law |
| BCS | Bengal Civil Service; British Computer Society |
| BD | Bachelor of Divinity |
| BDA | British Dental Association; British Deaf Association; British Dyslexia Association |
| Bdcasting | Broadcasting |
| Bde | Brigade |
| Bdrs | Borderers |
| BDS | Bachelor of Dental Surgery |
| BE | Bachelor of Engineering; British Element |
| BEA | British East Africa; British European Airways; British Epilepsy Association |
| BEAMA | Federation of British Electrotechnical and Allied Manufacturers' Associations (formerly British Electrical and Allied Manufacturers' Association) |
| BEC | Business Education Council |
| BECTU | Broadcasting, Entertainment, Cinematograph and Theatre Union |
| BEd | Bachelor of Education |
| Beds | Bedfordshire |
| BEE | Bachelor of Electrical Engineering |
| BEF | British Expeditionary Force; British Equestrian Federation |
| BEM | British Empire Medal |
| BEng | Bachelor of Engineering |
| Berks | Berkshire |
| BESO | British Executive Service Oversees |
| BFI | British Film Institute |
| BFPO | British Forces Post Office |
| BFSS | British Field Sports Society |
| BGS | Brigadier General Staff |
| BHS | British Horse Society |
| BICC | British Insulated Callender's Cables |
| BICSc | British Institute of Cleaning Science |
| BIM | British Institute of Management |
| BL | Bachelor of Law; British Library |
| BLA | British Liberation Army |
| Bldg Soc | Building Society |
| BLESMA | British Limbless Ex-Servicemen's Association |
| BLitt | Bachelor of Letters |
| Blvd | Boulevard |
| BM | British Museum; Bachelor of Medicine; British Monomark |
| BMA | British Medical Association |
| BMG | British Military Government |
| BMJ | British Medical journal |
| Bn | Battalion |
| BNAF | British North Africa Force |
| BNC | Brasenose College (Oxford) |
| BNEC | British National Export Council |
| BNOC | British National Oil Corporation; British National Opera Company |
| BNP | Banque Nationale de Paris |
| BOAC | British Overseas Airways Corporation |
| BOT | Board of Trade |
| BOTB | British Overseas Trade Board |
| Bp | Bishop |
| BPharm | Bachelor of Pharmacy |
| BPMF | British Postgraduate Medical Federation |
| BR | British Rail |
| BRA | British Rheumatism and Arthritis Association |
| BRB | British Railways Board |
| BRC(S) | British Red Cross Society |
| Brig | Brigadier |
| BRNC | Britannia Royal Naval College |
| bro | brother |
| BS | Bachelor of Surgery; Bachelor of Science; British Standard |
| BSA | Bachelor of Scientific Agriculture; Birmingham Small Arms; Building Societies' Association |
| BSAP | British South Africa Police |
| BSC | British Steel Corporation; Bengal Staff Corps |
| BSF | British Salonica Force |
| BSI | British Standards Institution |
| BSJA | British Show Jumping Association |
| BST | Bachelor of Sacred Theology |
| BT | Bachelor of Teaching; British Telecommunications |
| BTA | British Tourist Authority (formerly British Travel Association) |
| BTh | Bachelor of Theology |
| Bucks | Buckinghamshire |
| BUPA | British United Provident Association |
| bur | buried |
| BV | Besloten Vennootschap |
| BVMS | Bachelor of Veterinary Medicine and Surgery |
| BVSc | Bachelor of Veterinary Science |
| BWI | British West Indies |