Sir William Ivor Jennings KBE QC FBA (Sinhala: ශ්‍රීමත් අයිවර් ජෙනින්ග්ස්) (16 May 1903 – 19 December 1965) was a British lawyer and academic.

[1] Jennings joined the University of Leeds as a lecturer in law in 1925 and became a Holt Scholar of Gray's Inn and was called to the bar in 1928.

In 1955, Jennings received an honorary doctorate by vote of the senate of the University of Ceylon to recognize his work in creating and building the institution.

He subsequently served a term as Vice-Chancellor of the University of Cambridge, a position which at that time rotated among the heads of the colleges.

Together with his wife and daughter Claire, he was aboard the MS Lakonia, a Greek-owned cruise ship, when it caught fire and sank north of Madeira on 22 December 1963, with the loss of 128 lives.