| Complete stoves | Wood stove shop | Buffs Farm, Elkington Rd | Mon–Fri 09:00–17:00 |
| Compton Estates | Property management company | Estate Office | Mon–Fri 08:30–17:30 |
| Computer Repair Shop | Computer repair service | 163 Weedon Rd | Mon–Thu 10:00–17:00 |
| Conservatory4you | Conservatory contractor | Unit 2, Overstone Grange Farm, Kettering Rd | Mon–Tue 08:00–16:00 |
| Coopers & Co Ltd | Accountant | Thistledown Barn | Mon–Fri 09:30–16:30 |
| Corkers Champagne & Cocktail Bar | Cocktail bar | 361 to 363 Wellingborough Rd | Thu 16:00–23:00 |
| Coton Manor Garden | Botanical garden | Coton Manor Nr | Tue–Fri 11:00–16:00 |
| Creative Edge | Shopfitter | Unit 2 Deer Park Rd | Mon–Fri 08:00–17:00 |
| Crick Ex-Servicemen's Club & Institute | Club | Church St | Mon–Fri 16:00–00:00 |
| Crick Waterside & Marina | Marina | W Haddon Rd | Daily 09:00–16:30 |
| Cromwell Cottage Northampton | Gastropub | 1 High St | Mon–Thu 11:00–23:00 |
| Crown Northampton Ltd - Handmade Shoes & Sneakers - Since 1908 | Shoe factory | 86 Bunting Rd | Mon–Thu 09:00–16:00 |
| Curo Wealth | Investment company | Preston Court | Mon–Fri 08:00–19:00 |
| CW Plant Hire | Tool rental service | 88-90 High St | Mon–Fri 07:30–17:30 |
| Cyber Signs Ltd | Sign shop | 80 Tenter Rd | Mon–Fri 09:00–17:00 |
| D Electrics Northants Ltd | Solar energy company | 42 Ecton Park Rd | Mon–Sat 08:00–18:00 |
| D.E.N.T.L.U.K.E | Vehicle dent removal service | Unit 7, Redhouse | Mon–Fri 10:00–19:00 |
| Daro Indoor & Outdoor Furniture | Tienda de muebles | Industrial Estate, Heathfield Way, Kings Heath | Mon–Fri 09:00–17:00 |
| Deliciously Divine Cake Design | Wedding cake shop | Thorburn Rd | Tue–Fri 09:30–15:00 |
| Design Web Consultancy | Marketing consultant | Oxford House, Billing Rd, Cliftonville | Mon–Fri 09:00–17:00 |
| Designer Golf Ltd | Golf shop | Delapre Golf Centre, Eagle Dr, Nene Valley Way | Tue–Sat 08:30–17:00 |
| Desired lengths Ltd | Tanning salon | 232-234, Wellingborough Rd | Mon–Fri 09:00–19:00 |
| Direct Property Services | Apartment letting agency | 186 Kettering Rd | Mon–Fri 10:00–18:00 |
| Displaykit | Display stand manufacturer | 1 Hammas Leys | Mon–Fri 08:30–18:00 |
| DMS Flooring Supplies: Northampton | Carpet wholesaler | 8-9, Monarch Courtyard, Salthouse Rd | Mon–Fri 07:00–17:00 |
| Dodmoor House | Wedding venue | Dodmoor House, Weedon Lane | Mon–Fri 09:00–17:00 |
| Dodo Computing | Computer repair service | 34 East St | Mon–Fri 09:00–13:30 |
| DP Garage Ltd | Oil change service | 20-22 Tweed Rd | Mon–Fri 09:00–19:00 |
| Dream IT Solutions | Computer service | The Studio, 8 Sentinel Rd | Daily Open 24 hours |
| Duncan Spedding - Professional Anxiety Specialist | Mental health services | 2 Quebec Cl | Mon–Fri 09:00–21:00 |