See below for a list of companies we work with. OS receives a variety of goods and services and therefore looks to a broad range of suppliers.
| Advanced Resource Managers Limited | Recruitment |
| Advantage Resourcing UK Ltd. | Recruitment |
| Allwag Promtions Ltd | Promotional merchandise |
| Amazon EU SARL | Software, Hosting |
| Anything is Possible Ltd | Media buying |
| April Six Proof Ltd | Marketing |
| Arthur J Gallagher | Insurance brokerage |
| Banner | Stationery |
| Big Commerce | E-Commerce site |
| Calder Conferences Limited | Venues |
| Canon UK | Multi-functional devices |
| Capita Property & Infrastructure Ltd | Health & Safety services |
| CBRE Managed Services Ltd | Facilities management |
| Certes Computing | Recruitment |
| CMA Recruitment Group | Recruitment |
| Computacenter (UK) Ltd | Software, Hardware |
| Corona Energy Ltd | Gas |
| Corporate Travel Management (Redfern) | Travel |
| CTI Digital | Digital consultancy |
| Customer Consulting Ltd | Contact centre consultancy |
| Cyient Europe Limited | Data Production |
| DEA Aviation Limited | Aircraft Hire |
| Dennis Maps Ltd | Printed Map Production |
| Dynamite Recruitment | Recruitment |
| EDF Energy | Electricity |
| ESRI (UK) Ltd | Software, Professional Services |
| Evisa Solutions Ltd TA Malikshaw Interim & Executive | Recruitment |
| FDM Group Ltd | Junior engineer provision |
| Field Fisher Waterhouse LLP | Legal advice |
| Geoplan Spatial Intelligence Limited | Data Production |
| Glint Inc | Employee surveys |
| Google Ireland Limited | Software, Hosting |
| Green Park Interim & Executive Search | Recruitment |
| Hays Specialist Recruitment Ltd | Recruitment |
| HM Land Registry | Data Production |
| HRG Ltd | Point of Sale |
| Idealogy Ltd | Brand consultancy |
| IIC Technologies Limited | Data Production |
| Inform Limited | Communications services |
| Insight Direct (UK) Ltd | Software, Hardware |
| Intelligent Resource Ltd | Recruitment |
| International SOS Assistance UK Limited | International assistance |
| Kantar UK Limited | Customer experience tracking |
| Konica Minolta Business Solutions | Print room equipment |
| LA International Computer Consultants Limited | Recruitment |
| Landmark Information Group Limited | Data Production |
| Leasedrive Group/Zenith Vehicle Contracts Ltd | Fleet |
| Leica Geosystems Technology A/S | Hardware, Software |
| Leica Geosystems Technology A/S | Software, Hardware |
| Leica Geosystems Technology A/S (previously COWI A/S 101291) | GNSS infrastructure |
| Lifemarque Limited | Goods for re-sale |
| Lorien Resourcing Limited | Recruitment |
| Metia Ltd | Marketing |
| Michael Davies and Associates Limited | Warehousing & Distribution |
| Microsoft Ltd | Software, Hosting |
| Modis International Limited | Recruitment |
| Nexus Vehicle Management Ltd | Hire cars |
| Occupational Health Consultancy Ltd | Occupational health |
| Oracle Corporation UK Ltd | Software |
| Parcelforce Worldwide | Postal Services |
| Preloaded Limited | Mobile app development |
| QuantiQ Technology Limited | Professional Services |
| Randstad CPE Limited | Recruitment |
| Reed Specialist Recruitment | Recruitment |
| Robertson Bell Ltd | Recruitment |
| Royal Mail | Postal Services |
| SAP (UK) Limited | Software |
| Septentrio NV-107518 | GNSS infrastructure |
| Space 48 Limited | E-commerce site development |
| Spectrum IT Recruitment (South) Limited | Recruitment |
| Spinwell Global Ltd | Recruitment |
| Spyrosoft SA | Software, Professional Services |
| Survey Supplies Limited t/a KOREC | GNSS infrastructure |
| The Bridge (IT Recruitment Ltd) | Recruitment |
| The SEO Works Limited | SEO |
| Trimble EBV Ltd | GNSS infrastructure |
| Version1 Solutions Ltd | Software, Professional Services |
| Vexcel Imaging GmbH | Camera & associated technology |
| Vodafone Ltd | Telecommunications |
| White Space Strategy Ltd | Research |