Killian O’Reilly | Fieldfisher
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Professional background

Professional background

I specialise in the resolution of commercial disputes and have significant experience in commercial litigation, arbitration, construction disputes, insurance disputes and property related cases.

I advise clients on a wide variety of contractual claims, shareholder disputes, specific performance litigation, judicial reviews, professional indemnity claims, planning and environmental law, injunctions, and procurement law issues.

I represent most domestic and numerous international underwriters and re-insurers. I advise some of Ireland’s most successful organisations and regularly conduct High Court and Commercial Court litigation on their behalf.

I also represent employers at the Workplace Relations Commission and The Labour Court in respect of employment related disputes.

I advise clients on health and safety risks, defend organisations & executives in respect of Health and Safety Authority inspections and prosecutions, and represent clients in respect of coroner inquests and any related civil proceedings. 

I have specialist experience advising clients on cyber-crime and legal issues relating to cyber protection measures, and have also provided training in this area.In addition, I regularly advise clients in relation to technology disputes. 

I aim to provide advice that is clear and concise, communicating technical concepts in a way that is easily accessible for clients.

I am a CEDR accredited mediator who regularly represents clients in mediation and also acts as a mediator.

I regularly present lectures, training and workshops, for the Insurance Institute of Ireland and its members in relation to litigation and insurance matters.

Awards & recognition

Awards & recognition

Chambers Europe 2024
"Killian has an excellent understanding of his client's needs and develops appropriate strategies."
Chambers Europe 2023
He has a great commercial sense and offers very clear advice. He is an excellent adviser.
Killian O'Reilly - Legal 500 EMEA 2023
Killian O’Reilly is a top class lawyer  

Authored pieces

All Resources
Four men in business suits stand side by side, smiling, in front of a modern wooden wall. Three men wear dark suits with purple ties, and one wears a blue suit with a pink tie.
Dispute Resolution
Press Release

International Law Firm Fieldfisher Expands Dispute Resolution Offering with Appointment of Leading Dublin Partner Dermot McEvoy

16.09.2025
Fieldfisher Ireland LLP is delighted to announce the appointment of Dermot McEvoy as a partner in its Dublin Litigation and Dispute Resolution practice, effective 15 September 2025. Dermot joins from Eversheds Sutherland, bringing over 30 years of experience in construction and infrastructure disputes, commercial litigation, and alternative dispute resolution (ADR). His arrival marks a strategic expansion of Fieldfisher’s capabilities in high-value, complex disputes across Ireland and the UK.
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Two individuals sitting at a wooden table, with one holding a pen poised to write on a blank sheet of paper. Their hands are close together, suggesting collaboration or discussion. The focus is on their hands and the pen, with a blurred background.
Dispute Resolution
Insight

First of its kind Collective redress action in Ireland

29.05.2025
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Dispute Resolution
Insight

Adjudication Undone: Lessons from Tenderbids Limited v Electrical Waste Management

04.04.2025
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A person wearing a suit and tie is holding a magnifying glass in their right hand and examining a sheet of paper in their left hand. The background is blurred and has a dark, textured appearance.
Dispute Resolution
Insight

Tread carefully with fraud allegations

02.04.2025
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Dispute Resolution
Insight

Defamation (Amendment) Bill 2024 Back on Government Agenda

26.03.2025
In its 2025 Programme for Government, the Government has committed to passing the Defamation (Amendment) Bill 2024 as a "matter of priority" in 20251 . If enacted, the reforms set out in the Bill constitute a significant reform of defamation law in Ireland. 
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What others say…

Chambers Europe 2024
"Killian has an excellent understanding of his client's needs and develops appropriate strategies."
Chambers Europe 2023
He has a great commercial sense and offers very clear advice. He is an excellent adviser.
Killian O'Reilly - Legal 500 EMEA 2023
Killian O’Reilly is a top class lawyer