A by-election was held for the New South Wales Legislative Assembly seat of Bass Hill on 2 August 1986.
The by-election was triggered by the resignation of sitting Labor MP Neville Wran.
At the time, Wran held the record for the longest uninterrupted stint as NSW Premier.
Bass Hill was lost by the Labor Party for the only time in the history of the district.
In a very close result, Liberal Party candidate Michael Owen won the contest by 103 votes after the distribution of preferences.