| Election Name: | 1904 Isle of Thanet by-election |
| Type: | presidential |
| Country: | United Kingdom |
| Previous Election: | Isle of Thanet (UK Parliament constituency)#Elections in the 1900s |
| Previous Year: | 1900 |
| Next Election: | Isle of Thanet (UK Parliament constituency)#Elections in the 1900s |
| Next Year: | 1906 |
| Election Date: | 7 October 1904 |
| Candidate1: | Marks |
| Party1: | Conservative Party (UK) |
| Popular Vote1: | 4,048 |
| Percentage1: | 52.5% |
| Candidate2: | King |
| Party2: | Liberal Party (UK) |
| Popular Vote2: | 3,666 |
| Percentage2: | 47.5% |
| MP | |
| Posttitle: | Subsequent MP |
| Before Election: | James Lowther |
| Before Party: | Conservative Party (UK) |
| After Election: | Harry Marks |
| After Party: | Conservative Party (UK) |
The 1904 Isle of Thanet by-election was held in the UK Parliament constituency of the Isle of Thanet on 7 October 1904, following the death of Conservative Party MP James Lowther. It was successfully defended for the Conservative party by Harry Marks.
Conservative Party MP James Lowther died on 12 September 1904, triggering a by-election to fill the vacancy.[1]
The Isle of Thanet seat had been held by the Conservative party since its creation in 1885. In the 1900 general election Conservative candidate James Lowther was elected unopposed.
In anticipation of a forthcoming general election, the local Liberal association, about 6 months earlier, had selected 44 year old Joseph King as their candidate. He lived in Surrey, where he had previously been elected to the county council.[2]
The usually Conservative supporting newspaper The Times, took a position in opposition to the Conservative candidate.[3]
Marks held the seat at the subsequent general election.Marks would go on to represent the constituency until retiring in 1910.