2017 Blacktown state by-election

A by-election was held in the state electoral district of Blacktown on 14 October 2017. The by-election was triggered by the resignation of John Robertson. Robertson served as state Leader of the Opposition from 2011 until 2014.

The by-election was held on the same day as by-elections Cootamundra and Murray.

Candidates
The candidates in ballot paper order are as follows:

Results
John Robertson resigned.