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Gillian O'Shaughnessy
  • Azets Ireland

    ByrneWallace LLP advises the partners in accountancy and business advisory firm Baker Tilly Ireland....

  • PrecisionBiotics Group Limited

    ByrneWallace advised leading Irish probiotics company, PrecisionBiotics Group Limited....

  • Cosmo Pharmaceuticals

    Acting as Irish legal advisor to publicly traded specialty pharmaceutical company....

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Gillian qualified as a solicitor in January 2004 and joined the firm in 2007 having previously trained and worked in the corporate department of another top tier Irish law firm. 

Gillian has extensive experience advising Irish and international clients on a wide range of public and private corporate transactions, including mergers & acquisitions, corporate fundraisings and restructurings and joint venture arrangements. She also advises in relation to corporate governance, company law compliance, establishment in Ireland and shareholder arrangements.  Gillian's practice area encompasses advice to businesses on general commercial arrangements, with a particular focus on outsourcing agreements.  She has advised clients on the corporate and commercial law aspects of Commercial Court proceedings.  Her clients operate in sectors including clean-tech/renewable energy, technology, life sciences, financial services, insurance, logistics and property.  

Key transaction experience

  • Acting for large public clean-tech/environmental services group in relation to a number of private company acquisitions;
  • Acting for service providers in the insurance, IT and private healthcare sectors in relation to outsourcing arrangements;
  • Acting for large Irish outsourcing group in relation to both public and private company acquisitions and re-financings;
  • Providing corporate advice to insurance provider in respect of its corporate structure, corporate governance matters, shareholding arrangements and expansion of operations;
  • Advice to individual shareholders in the context of a high value acquisition of an Irish software company;
  • Provision of company law advice in relation to corporate restructurings to two large corporate groups in the property development sector;
  • Acting for client in life sciences sector in relation to a number of fundraisings, including an Enterprise Ireland investment, a rights issue and a BES investment;
  • Acting for public company in property development sector in relation to two high-value corporate fundraisings;
  • Corporate advice to management in the context of proposed MBOs in the manufacturing, professional services and property sectors;
  • Provision of advice to large corporate client on corporate and company law issues arising in relation to Commercial Court proceedings.


  • B.A. (Hons) in English and History from NUI, Galway
  • LL.B. (Hons) from NUI, Galway
  • LL.M. (European & International Law) (Hons) from University of Edinburgh
  • Admitted to the Roll of Solicitors in England and Wales


  • DSBA Business and Commercial Law Committee
  • Firm representative to Irish Wind Energy Association
  • Law Society of Ireland
  • Dublin Solicitors Bar Association


'Gillian O’Shaughnessy is one of the most precise legal brains in corporate law in Ireland. She looks around legal corners to cover off risks.'  - Legal 500, 2023