The move comes after Dundee United were hammered 5-1 by Ross County on Saturday - Laszlo's 17th defeat in a brief spell in charge at Tannadice.
The Hungarian was in charge for 44 games, winning 18 of them and drawing the remainder. He leaves with them situated five points behind table-toppers, Ayr.
Laurie Ellis will take temporary charge of first-team duties.
"I would like to thank Csaba for the considerable commitment he showed during his time at Dundee United and for his contribution to improving the underpinning football structure at the Clu," chairmain Mike Martin said in a statement.
"We wish him all the best for the future. I can also confirm that Laurie Ellis has taken interim management responsibility for the team."