John Robertson Labor Stephen Bali Labor 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 (Labor).

[1] 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.

The candidates in ballot paper order are as follows:[2]