Under GDPR legislation, there are key roles that can help determine who is responsible for demonstrating compliance:
Data subject
A data subject is the individual to whom the collected personal data belongs. Personal data refers to anything that can be used to identify an individual, including name, passport number, financial records, address or employment details.
Under GDPR legislation, data subjects have rights to ensure that their personal information is stored securely, that their right to privacy remains intact, and to prevent organisations from deviating from GDPR rules.
Data controller
A data controller is a person or organisation who decides how a data subject’s personal data will be collected and for what purpose. It’s the data controller‘s responsibility to:
- Be accountable for lawfully collecting personal data.
- Create strict security measures, such as encryption, to protect data from unlawful access.
- Report data breaches if such an incident occurs.
Sometimes, there may be more than one data controller within an organisation. When Data Controllers decide on the purpose of personal data collection, they must ensure confidentiality and that no one or no organisation can access that personal data unauthorised or unlawfully.

Data processor
A data processor is an individual or third party who processes gathered personal data at the data controller’s request. A data processor‘s primary responsibilities include:
- Always acting under the specified role the data controller has given them.
- Processing collected personal data if the data controller permits it.
- Ensure that when processing data, GDPR is complied with.
Data protection officer
The data protection officer (DPO) is responsible for compliance GDPR throughout an organisation’s whole data collecting process. A data protection officer‘s responsibilities can include:
- Advising organisations on appropriate measures to take in data collection strategies.
- Inform organisations they have a responsibility to comply with GDPR laws.
- Monitor compliance.
Appointing a DPO is only mandatory in one of three situations:
- When your organisation is a public authority or body;
- If processing data subjects on a large scale;
- If performing large scale processing of special categories of personal data and data relating to criminal conviction
Organisations may decide to assign someone already in their organisation in the role of DPO in addition to existing duties, rather than hire externally for a dedicated position.
Supervisory authority
As well as understanding who is responsible for demonstrating compliance with GDPR within an organisation, national supervisory authorities help oversee GDPR compliance and personal data protection within EU countries.
Ireland’s supervisory authority is the Data Protection Commission. It is responsible for upholding the rights of Irish citizens to have their personal data protected under GDPR legislation.
