Arriva will not be operating bus services in Halifax, Dewsbury, Heckmondwike, Cleckheaton, Batley, Castleford, Pontefract, Bradford, Leeds, Ossett, Morley, Rothwell, South Elmsall, Hemsworth, Huddersfield, Doncaster, Selby, York or Goole until the strike is over.
The indefinite action involves bus drivers and engineers who are members of Unite and based at depots in Castleford, Dewsbury, Heckmondwike, Selby and Wakefield.
Unite claims that Arriva’s "low pay" across Yorkshire means bus workers are struggling to make ends meet amid the cost of living crisis.
Gavin Peace, Area Operations Director for Arriva North East and Yorkshire, said: “We are extremely disappointed that Unite are pressing ahead with strike action for an indefinite period across services in Yorkshire.
"There is simply no justification for this action which will seriously inconvenience communities across Yorkshire, including students travelling for their GCSE exams."