| Love and Luna Astrology | Astrologer | Brunswick Square | Daily 09:00–21:00 |
| M.K.Electrical Brighton | Electrician | Ringmer Dr | Thu Open 24 hours |
| Make New Again | Photo restoration service | 19 Oxford St | Mon–Thu 09:00–17:00 |
| Maplewood Tree Surgery | Arborist service | 140 Hollingdean Terrace | Thu Open 24 hours |
| Martlet Kayak Club | Club | 294 Madeira Dr | Tue 17:30–19:30 |
| Master Tiles | Tile shop | Tates Crossroads, 135 Trafalgar Rd, Old Shoreham Rd | Mon 07:30–17:00 |
| Melissa Foreman Homeopath/Naturopath | Naturopath | Roedean Crescent | Fri 10:00–17:00 |
| MetLife UK | Insurance agency | Blackmore Ct | Mon–Fri 09:00–17:00 |
| Meynell Gunton Architects | Architect | 8, Beaconsfield Studios, 25 Ditchling Rise | Mon–Fri 09:00–17:30 |
| Miranda Mather | Dressmaker | 68 North Rd | Mon 10:00–18:00 |
| Mohammed - Spice Of Life | Bangladeshi restaurant | Unit 19, Marshalls Row | Mon 10:00–18:00 |
| MPM Specialist Solutions Ltd | Graffiti removal service | Maritime House, Basin Rd N | Mon–Thu 09:00–17:00 |
| MS Roofing Supplies Portslade | Roofing supply shop | Basin Rd N | Mon–Fri 07:00–16:30 |
| Murasaki Restaurant | Authentic Japanese restaurant | 115 Dyke Rd | Tue 17:00–22:00 |
| My Turkish Delight Kitchen | Doner kebab restaurant | 76 Preston St | Thu–Fri 12:00–02:00 |
| Natalie The Doula | Doula | 7 Cedars Gardens | Daily Open 24 hours |
| Natural World Safaris Ltd | Tour operator | 127 Gloucester Rd | Mon 09:00–20:30 |
| Neutral Reformer | Pilates studio | Clermont Hall, Cumberland Rd | Mon–Thu 06:00–20:00 |
| Nick Ford Photography | Photography studio | 19 Oxford St | Thu 09:00–17:30 |
| Nikhil Maini Oral and Maxillofacial Surgeon | Oral and maxillofacial surgeon | Nuffield Health, Hospital, Warren Rd | Fri 09:00–14:30 |
| No No Please | Pan-Asian restaurant | 30 Preston St | Wed 18:00–21:00 |
| NPS - Probation Office | Prison | Lancaster House, 47 Grand Parade | Mon–Fri 09:00–17:00 |
| nua Pilates | Pilates studio | 10-12 Lewes Rd | Mon–Thu 07:00–16:00 |
| Oakbury Watches | Watch shop | 30 North St | Mon–Fri 09:30–17:00 |
| Old Skool Bus & Kitchen - Event Catering FOOD TRUCK | Mobile caterer | 7A Church St | Daily 09:00–18:00 |
| Omgtea | Tea shop | Nile House, Nile St | Tue–Wed 09:00–17:00 |
| Orelia | Jewelry store | 5 Prince Albert St | Sun 11:00–17:00 |
| Outpost Music Exchange | Guitar shop | 76 North Rd | Mon–Sat 10:30–17:30 |
| Paddenburg and Co (Brighton Tax) | Chartered accountant | 100 Church St | Thu 09:00–17:00 |
| Paddleboard Hire Brighton | Sports equipment rental service | Hove Town Hall | Tue 09:00–17:30 |