| Honorific Prefix: | The Right Honourable |
| Sir John Hay, Bt | |
| Office: | Member of Parliament for Peeblesshire |
| Term Start: | 1831 |
| Term End: | 1837 |
| Predecessor: | Sir George Montgomery, Bt |
| Successor: | William Forbes Mackenzie |
| Parents: | Sir John Hay, 5th Baronet Hon. Mary Elizabeth Forbes |
| Relations: | Sir Adam Hay, 7th Baronet (brother) |
Sir John Hay, 6th Baronet of Smithfield and Haystoun FRSE FSA (3 August 1788 – 1 November 1838) was a British baronet and politician.
He was the eldest surviving son of Sir John Hay, 5th Baronet of Smithfield and Haystoun FRSE, banker and landowner, and the Hon. Mary Elizabeth Forbes. His brother-in-law was the banker, George Forbes FRSE.
He trained as an advocate and passed the Scottish bar in 1811. In 1820 he was elected a Fellow of the Royal Society of Edinburgh his proposer being George Forbes.[1]
He sat as a Member of Parliament for Peeblesshire from 1831 to 1837.
In 1821 he married Ann Preston. They had no children.
Upon his death on 1 November 1838, he was succeeded in the baronetcy by his younger brother, Adam.[2] He is buried at the Cross Kirk, Peebles in the enclosed area to the south.