| Election Name: | 1903 East Sydney by-election |
| Ongoing: | no |
| Turnout: | 2,073 (15.06%) |
| Next Year: | 1903 |
| Next Election: | 1903 Australian federal election |
| Election Date: | 18 August 1903 |
| Previous Year: | 1901 |
| Previous Election: | 1901 Australian federal election |
| Type: | Parliamentary |
| Seats For Election: | The East Sydney seat in the House of Representatives |
| After Party: | Free Trade Party |
| Candidate3: | John Blake |
| Party3: | Independent (politician) |
| Percentage3: | 4.68% |
| Popular Vote3: | 96 |
| Swing3: | 4.68 |
| Registered: | 13,763 |
| Candidate1: | George Reid |
| Popular Vote1: | 1,697 |
| Popular Vote2: | 259 |
| After Election: | George Reid |
| Before Party: | Free Trade Party |
| Before Election: | George Reid |
| MP | |
| Swing2: | 12.62 |
| Percentage2: | 12.62% |
| Party2: | Protectionist Party |
| Image1: | George Reid cph.3c31684.jpg |
| Candidate2: | William Maguire |
| Swing1: | 14.67 |
| Percentage1: | 82.70% |
| Party1: | Free Trade Party |
| Country: | Australia |
A by-election was held for the Australian House of Representatives electorate of East Sydney in New South Wales on 4 September 1903, a Friday. It was triggered by the resignation of George Reid on 18 August 1903. The writ for the by-election was issued on 20 August, nominations for candidates closed on 27 August.
At the time of his resignation, Reid was the leader of the Free Trade Party and the first Australian Opposition Leader. He resigned in protest on the day that a bill was passed in the parliament regarding the allocation of electoral boundaries for the state of New South Wales.[1]
Reid was returned as member for East Sydney with an increased majority. He was the first member of the House of Representatives to resign, and was the only person in federal parliamentary history to win back their own seat in a by-election after resigning until John Alexander did the same at the Bennelong by-election.