The American has walked away from the club 18 matches into the season with the Bullets having suffered 13 losses and sat in the penultimate position of the NBL standings.
“After a lot of thought and discussions I’ve decided to step down as Head Coach of the Brisbane Bullets,” Lash said in a club statement.
“We went into this season with excitement and expectations.
“I want nothing but success for the players, staff, fans and sponsors and will continue to support the club.”
Lash was reportedly in discussion with the club about his immediate future only halfway through the team's horrific six-game losing streak in which they have suffered four margins of 24 points or greater against them.
The Bullets began NBL26 hopeful of a playoffs appearance having built a strong roster that included NBL star Casey Prather and overseas imports Jaylen Adams and Javon Freeman-Liberty.
The joys of a nine-point season opening win over the NZ Breakers was short-lived, with the Bullets quickly falling to a 1-4 record. They lost Freeman-Liberty unexpectedly in late September, released Adams for poor performance in November, and Prather suffered a season-ending knee injury in mid-November.
Freeman-Liberty returned to the court this month but has failed to make a meaningful impact as the Bullets continue to slide down the ladder.
Lash was in his first year of a three-season contract and will be succeeded on a temporary basis by Assistant Coach Darryl McDonald.
Bullets CEO Mal Watts confirmed the club is "actively engaged in advanced discussions regarding our next Head Coach", suggesting that Lash's demise has been a long time coming.
