Theresa Castle

Senior Trade Mark Attorney

Theresa has experience in a wide range of contentious and non-contentious trade mark, design and domain name matters.

She has advised clients at every level, in all aspects of brand protection and enforcement. She has worked with clients throughout the lifecycle of their brands including on strategic portfolio management, clearance, prosecution, oppositions and cross border disputes.

Her experience spans sectors such as consumer products, entertainment, food and drink, TMT, financial institutions and healthcare. Theresa is heavily involved in the International Trade Mark Association (INTA), as a project lead on the Indigenous Rights Committee and also sits on the Chartered Institute of Trade Mark Attorneys’ (CITMA) Net Zero working group.

Leadership Positions And Professional Affiliations

  • Ordinary Member, Chartered Institute of Trade Mark Attorneys
  • Indigenous Rights Committee Member, International Trademark Association



Admitted as a Chartered UK Trade Mark and Design Attorney, 2012


Professional Certificate in Trade Mark Practice, Intellectual Property Law, Nottingham Trent University, 2012

IP Litigation Certificate, 2012

Certificate in Trade Mark Law and Practice, Intellectual Property Law, Queen Mary University of London, 2011

BA in Law, Carleton University, Canada, 2003


A&O Shearman was formed on May 1, 2024 by the combination of Shearman & Sterling LLP and Allen & Overy LLP and their respective affiliates (the legacy firms). Any matters referred to above may include matters undertaken by one or more of the legacy firms rather than A&O Shearman.