| Big Rock Bond | Rock climbing gym | Unit 4 Bond Ave | Sat 09:00–20:00 |
| Big Rock Hub | Rock climbing gym | Mandeville Dr | Sat 09:00–18:00 |
| Birch Landscapes | Landscape designer | 4 White Horse Yard | Mon–Sat 09:00–17:00 |
| Biserica Ortodoxa Romana Sfantul Gheorghe Pelerinul - Parohia Milton Keynes 2 | Eastern Orthodox church | Church St | Sun 12:00–15:30 |
| Bletchley Barrels - Reclaimed Oak Barrels and Planters | Barrel supplier | 14 Windmill Hill Dr | Mon–Tue 09:00–18:00 |
| Bletchley Leisure Centre | Leisure centre | Princes Way | Sun 07:00–19:00 |
| Bletchley Mobiles | Mobile home supply shop | Ground Floor, 2 Albert St | Mon–Sat 09:00–19:00 |
| Bletchley Scaffolding Ltd | Scaffolding service | Greenway Business Park | Mon–Fri 09:00–17:00 |
| Blind & Film Company | Window supplier | 1 Isling Brook | Wed–Thu 08:00–18:00 |
| Bloom | Electrolysis hair removal service | Unit 1, The Barn, Oliver's Field, Whaddon Rd | Tue 10:00–18:00 |
| Bluewire Hub Ltd | Energy advisory service | Ste 112, 548 - 550 Elder Gate | Mon–Fri 09:00–17:00 |
| Bobbis Aesthetics & Piercing | Body piercing shop | Unit 3, 2a Cambridge St | Tue–Fri 10:30–17:00 |
| Body Rule | Pilates studio | 6 Canon Harnett Ct | Mon 08:00–20:00 |
| Bona Limited | Flooring contractor | 8 Thornton Chase | Mon–Fri 09:00–17:00 |
| Bonners Piano Centre - Milton Keynes | Piano shop | 1 Ward Rd | Mon–Tue 10:00–17:00 |
| Boxing Lounge | Boxing gym | 407 Hayley Ct | Mon–Thu 06:00–19:30 |
| Braid Barbers | Hairdresser | 769 Midsummer Blvd | Tue 09:30–19:00 |
| Breakthrough Family Law Solicitors (Milton Keynes) | Family lawyer | Office 2, Mount House C, Bond Ave | Mon–Fri 08:00–20:00 |
| Bricknall's PC Services Ltd | Computer consultant | Regents Hall, St Mary's Ave | Mon–Fri 09:00–17:00 |
| Bridge Autocare | MOT centre | 3 Bridgeturn Ave | Thu 09:00–18:00 |
| British Face Clinic - Deep Plane Facelift & Rhinoplasty Milton Keynes | Plastic surgery clinic | Athena Surgical Centre, 16 Davy Ave | Mon–Sat 08:00–18:00 |
| Broadbase PM & QS Services Ltd | Quantity surveyor | 180 Oldbrook Blvd | Mon–Fri 09:00–17:00 |
| Brooklands Health Centre | Medical centre | Montague Cres | Mon–Fri 08:00–18:30 |
| Browns Tree Solutions Ltd | Arborist service | Unit 10, Lower Rectory Farm, Mill Ln | Thu 08:00–16:00 |
| BSH Home Appliances Ltd | Corporate office | Grand Union, Old Wolverton Rd | Mon–Fri 08:30–17:30 |
| BSI | Certification agency | Davy Avenue Knowlhill | Mon–Fri 09:00–17:00 |
| Bucks General Surgery | Surgeon | V7 Saxon St, Chadwick Dr | Mon Open 24 hours |
| Budgie-Print | Graphic designer | 16 Kirkstall Pl | Mon–Sat 09:00–18:00 |
| Bumble Bees Ltd | Tree service | 5 Telford Way | Mon 08:00–17:00 |
| BW Glazing and Locks | Glazier | 10 Merlin Walk | Mon–Fri 08:00–18:00 |