| Election Name: | 1918 Taranaki by-election |
| Country: | New Zealand |
| Flag Year: | 1918 |
| Type: | By-election |
| Ongoing: | no |
| Previous Election: | 1914 New Zealand general election |
| Previous Year: | 1914 general |
| Next Election: | 1919 New Zealand general election |
| Next Year: | 1919 general |
| Turnout: | 74.19% |
| Candidate1: | Sydney George Smith |
| Colour1: | FFBBBB |
| Party1: | Independent Labour |
| Popular Vote1: | 2,840 |
| Candidate2: | John Connett |
| Party2: | Reform Party (New Zealand) |
| Popular Vote2: | 2,680 |
| Member | |
| Before Election: | Henry Okey |
| After Election: | Sydney George Smith |
| Before Party: | Reform Party (New Zealand) |
| After Party: | Independent Labour |
| Result: | Independent Labour gain from Reform |
The Taranaki by-election of 1918 was a by-election in the electorate on the west coast of the North Island. It was held during the 19th New Zealand Parliament, on 10 October 1918. It was caused by the death of incumbent MP Henry Okey of the Reform Party and was won by Sydney George Smith, the son of previous Taranaki MP Edward Smith, who stood as an independent Labour candidate. Smith supported the war effort unlike most Labour politicians, gaining him support of voters who likewise supported the war.
The following table gives the election results: