- Oliver RyanConstituency: BurnleyParty: Labour (Co-op)
- Olivia BaileyConstituency: Reading West and Mid BerkshireParty: Labour
- Olivia BlakeConstituency: Sheffield HallamParty: Labour
- Olly GloverConstituency: Didcot and WantageParty: Liberal Democrat
- Órfhlaith BegleyConstituency: West TyroneParty: Sinn Féin