| Alistair Hay | |
| Occupation: | Botanist |
| Relatives: | Edward Hay (brother) Edward Hay (grandfather) Osbert Peake (grandfather) |
Lord Alistair Hay (born 1955) is an Australian botanist. He is a former director of the Royal Botanic Garden, Sydney. He is the heir presumptive to his older brother Charles Hay, 14th Marquess of Tweeddale (born 1947).