Ian Macgregor (born c. 1937) is a British investment executive and chartered accountant. He is the former chief investment officer of The Wellcome Trust, oversaw growth of nearly £1bn per annum over fifteen years. The Wellcome Trust was the then-largest foundation in the world, with total assets valued at about £14bn at his retirement in 2000.^[1] Regarded by many as the most successful investment officer ever seen in the not-for-profit sector, Macgregor was behind the largest private share sale on record: initial flotation of Wellcome Plc.

He was a judge in the 2001 UK Charity Awards.^[2] and has served as a non-executive director for International Biotechnology Trust PLC.^[3] As President of Charity Tax Group (formerly Charity Tax Relief Group), he lobbied for VAT exemption for UK based charities.^[4]

He has also served as a Royal Commissioner of the Royal Commission for the Exhibition of 1851, alongside those such as Sir James Dyson and President Prince Philip, Duke of Edinburgh.