The Grey by-election of 1913 was a by-election during the 18th New Zealand Parliament, held on the 24th of July. A by-election or bye-election (called special election in the United States) is an Election held to fill a political office that has become vacant The seat became vacant due to the death of Arthur Guinness. Sir Arthur Robert Guinness ( 11 January 1846 – 10 June 1913) was a New Zealand Politician, and Speaker of the House Three candidates contested the seat, and it was won by the left-wing candidate, who was elected on the second ballot with Liberal support:
| Name | Party | First Ballot | Second Ballot | Percentage | |
| Paddy Webb | Social Democrats | 2,091 | 3,477 | 55. This article is about the original New Zealand Liberal Party At least three subsequent organisations unconnected to the original have used the same name the Liberal Party Patrick Charles (Paddy Webb 30 November 1884 &ndash 23 May 1950) was a New Zealand trade unionist and politician The Social Democratic Party of New Zealand was an early Left-wing political party 3% | |
| Henry Michel | Reform | 2,189 | 2,811 | 44. The Reform Party was New Zealand 's second major Political party, having been founded as a conservative response to the original Liberal Party 7% | |
| Michael Hannan | Liberal | 2,039 | N/A | N/A |