The are several differences between a CIO and a CTO, notably:
- A CIO is responsible for maintaining/expanding the internal IT infrastructure, and developing for products/services that are for internal usage/consumption. The CTO is responsible for developing IT products/services for external clients. (Note: The project manager reports to the CIO in case of a internal project, and to the CTO in case of an external project).
- The CIO usually deals with internal stakeholders, the CTO deals with external stakeholders.
- The CIO procures technology equipment/software to serve the internal infrastructure/projects, the CTO procures equipment/software to serve external projects.
- A CIO is focused on the internal IT operations (such as maintaining/expanding the IT infrastructure, developing IT products/services for internal use, IT procurement for the company), the CTO is focused on the external IT operations (such as developing IT products/services for external customers)
- In large companies where resources are completely segregated, the CIO will be either responsible or influential in hiring resources to serve the internal operations, the CTO will be responsible/influential for hiring resources to serve the external operations.
- The CIO is focused on enhancing the internal IT operations of the organization (and ultimately productivity and efficiency), the CTO is responsible for increasing the revenue of the company by undertaking external projects.
In short, the CIO is focused on internal operations of the company, while the CTO is focused on the external operations of the company.