| Country: | Western Australia |
| Type: | parliamentary |
| Ongoing: | no |
| Election Date: | 17 March 2018 |
| Candidate1: | David Honey |
| Party1: | Liberal Party of Australia |
| Popular Vote1: | 10,872 |
| Percentage1: | 59.9% |
| Swing1: | 3.2pp |
| Candidate2: | Greg Boland |
| Party2: | Australian Greens |
| Popular Vote2: | 3,555 |
| Percentage2: | 19.6% |
| Swing2: | 7.5pp |
| 1Blank: | TCP |
| 2Blank: | TCP swing |
| 1Data1: | 70.2% |
| 2Data1: | 6.9pp |
| 1Data2: | 29.8% |
| 2Data2: | 29.8pp |
| MP | |
| Before Election: | Colin Barnett |
| Before Party: | Liberal Party of Australia |
| After Election: | David Honey |
| After Party: | Liberal Party of Australia |
A by-election for the electoral district of Cottesloe in Western Australia took place on 17 March 2018.[1] The by-election was triggered by the resignation of the Liberal Party member, Colin Barnett, on 5 February 2018. Barnett was the Premier of Western Australia from 23 September 2008 until 17 March 2017, when he was succeeded as Premier by Mark McGowan after the Labor Party defeated Barnett's Liberal government at the 2017 state election in March 2017. The by-election was won by the Liberal candidate David Honey.
The writ for the by-election was issued by the Speaker of the Legislative Assembly, Peter Watson, on 6 February 2018.[2]
The by-election was held on 17 March 2018, the same day as the South Australian state election and the Batman federal by-election.[3]
The Labor Party announced it would not nominate a candidate for the by-election.[4]
| Candidates in ballot paper order[5] | |||||
|---|---|---|---|---|---|
| Party | width=10% | Candidate | width=78% | Background | |
| width=3pt | Liberal | David Honey | Honey is a manager at Alcoa, president of the Kwinana Industries Council and former state president of the Liberal Party in Western Australia.[6] | ||
| width=3pt | Micro Business | Cam Tinley | Contested the Legislative Council at the 2017 state election.[7] | ||
| width=3pt | Independent | Michael Thomas | Running to advocate for completion of the Perth–Fremantle PSP Bike Path.[8] | ||
| width=3pt | Western Australia | Ron Norris | Former mayor of Mosman Park. | ||
| width=3pt | Greens | Greg Boland | Previously contested Cottesloe for the Greens at three state elections. | ||
| width=3pt | Independent | Michael Tucak | Member of the Cottesloe Town Council. Contested the Legislative Council at the 2017 state election. | ||
| width=3pt | Independent | Dmitry Malov | Previously contested Cottesloe at the 2017 state election.[9] | ||