Sir William Ivor Jennings KBE QC FBA (Sinhala: ශ්රීමත් අයිවර් ජෙනින්ග්ස්) (16 May 1903 – 19 December 1965) was a British lawyer and academic. He served as the vice chancellor of the University of Cambridge (1961–63) and the University of Ceylon (1942–55).