Elizabeth Susan Wilmshurst CMG KC (born 28 August 1948), Distinguished Fellow of the International Law Programme[1] at Chatham House (the Royal Institute of International Affairs), and Professor of International Law at University College London, is best known for her role as Deputy Legal Adviser at the Foreign and Commonwealth Office of the United Kingdom on the eve of the 2003 invasion of Iraq.

She resigned from the Foreign Office on 20 March 2003, three days after Lord Goldsmith's final advice[2] to the British government reversed her legal opinion (in Lord Goldsmith's first secret memo 10 days earlier[3]) that the invasion was illegal without a second United Nations Security Council Resolution to SCR 678.

[8] Her writings and publications in the complex area of International Criminal Law include the widely used An Introduction to International Criminal Law and Procedure, co-edited with Robert Cryer, Hakan Friman and Darryl Robinson.

[9] Juliet Stevenson played Wilmshurst in "A Simple Private Matter", an episode of the BBC series 10 Days to War.

She is also played by Tamsin Greig in the film Official Secrets about Katharine Gun's leaking of the GCHQ memo.