| Malo Empanadas Kemptown | Argentinian restaurant | 90 St James's St | Mon–Sat 11:00–18:00 |
| Mayberry Garden Centre | Garden centre | 7-17 Old Shoreham Rd | Mon–Sat 08:30–18:00 |
| Maz's Kitchen Ltd | Cooking class | 17 Elvin Cres | Mon–Sat 09:00–23:00 |
| MDTea | Tea wholesaler | Unit 27, Open Market, Marshalls Row | Mon–Sat 10:30–17:30 |
| Mercedes-Benz of Brighton | Mercedes-benz dealer | Victoria Rd | Mon–Fri 08:00–18:30 |
| Mermaid Brighton beauty salon | Beauty salon | 116 Dyke Rd | Mon–Thu 10:00–20:00 |
| Mexico Real Cafe | Tea and coffee shop | 4th Floor, 44 North Rd | Daily 08:00–18:00 |
| Mile Oak Farm | Farm | Mile Oak Rd | Mon–Sat 09:00–17:00 |
| Mills N Blooms | Florist | Crowhurst Corner, 7 Crowhurst Rd | Daily 03:00–09:30 |
| Mishkin's Music Academy / Nest Studios | Piano instructor | 22 Kingsbury Rd | Daily 09:00–21:00 |
| Model Talent UK | Modelling agency | Royal Alexandra Quarter, 10 Beves, Dyke Rd | Daily 09:00–21:00 |
| Moksha Caffe | Brunch restaurant | 4-5 York Pl | Mon–Fri 08:00–16:00 |
| Money 4 Travel - Essiell Ltd | Software company | Park Gate, 161-163, Preston Rd | Daily 08:00–17:00 |
| Monster Studios | Rehearsal studio | Monster Studios, Maritime House, Basin Rd N | Daily 10:00–00:00 |
| MOONLIGHT Pan Asian Cuisine | Indonesian restaurant | 31-32 New Rd | Mon–Fri 12:00–22:00 |
| Motorway | Car auction | Motorway, 16, 17 West St | Daily 09:00–19:00 |
| Moulsecoomb Social Club | Social club | Moulsecoomb Hall, Lewes Rd | Mon–Tue 16:00–23:00 |
| Mōwai Coffee Roasters | Coffee shop | 11 St James's St | Mon–Sat 07:30–17:30 |
| MrCutters | Gardener | Richmond Terrace | Daily Open 24 hours |
| Naija Corner Restaurant | West African restaurant | 60 Preston St | Mon–Sat 13:30–23:00 |
| NEON ART by Ash | Neon sign shop | 19 Market St | Tue–Sun 09:00–17:00 |
| New School Kebab Wrap & Grill | Kebab shop | 38 Lewes Rd | Mon 14:00–23:00 |
| Noodle Bang 拌碗拌粉面馆 | Chinese noodle restaurant | 61 Queens Rd | Mon 11:30–21:30 |
| Noolibird Ltd | Rubber stamp shop | Woodland Walk | Daily 09:00–17:00 |
| North Laine Music | Musical instrument shop | 44 Sydney St | Mon–Fri 11:30–17:30 |
| Overgrown | Organic shop | 42 Sydney St | Sun 11:00–18:00 |
| P P M Engineers Ltd | Material handling equipment supplier | 4 Briarcroft Rd | Daily 08:00–18:00 |
| Panserve | Information services | Runway East, 50 New England St | Daily Open 24 hours |
| Parish Church of the Holy Cross, Wooding Dean | Church of england church | Church of the Holy Cross, 2 Downsway | Daily 09:00–18:00 |
| Patcham Methodist Church | Methodist church | Ladies' Mile Rd | Sun 10:30–11:30 |