Metro said it had received notification the firm had ceased operations.
“We are working hard to ensure disruption is kept to a minimum and are seeking alternative operators to cover the following services,” it said.
The services affected include:
Service 30 – Horsforth – Pudsey (off peak service)
Service 61 – St James Hospital – Hunslet (South Leeds Stadium)
Service 116 – Leeds – Ossett – Wakefield
Service 118 – Wakefield – White Rose Centre (evenings only. Daytime service operated by Arriva is not affected)
Service 212 – Wakefield – Batley – Dewsbury
Service 1 – Leeds – Wakefield is also affected.
The West Yorkshire Combined Authority added that “passengers are advised to check the Metro website for updates to routes”.
The mother of a 17-year-old girl who uses Yorkshire Buses to travel to college said she hoped an alternative would be found after Easter.
Terri’s daughter travels on the firm’s 116 route from Gawthorpe into Leeds.
“Obviously she’s looked and found out that bus is no longer going to be running,” Terri said.
“So she’s been unable to get to college today. Obviously if she can’t attend college it could impact her education.”
Terri said she started work too early to drive her daughter into Leeds and was not aware of any other bus route that her daughter could access to get to college for 09:00.
The firm’s two school bus routes served Woodkirk Academy in Tingley and Bruntcliffe Academy in Morley.
The company also operated a service between Doncaster and Norton.
A South Yorkshire Mayoral Combined Authority spokesperson said the service was a single contracted Sunday service and it was “working at pace to ensure passengers are protected”.
“We are already moving to put alternative arrangements in place so that people can continue to travel as normal. Our priority is ensuring there is no disruption for local communities.”