Saskatchewan's Court of Appeal is to release its ruling this week on whether the federally imposed carbon tax is constitutional.
A registrar for the court says the decision is to be posted online Friday at noon.
The Saskatchewan Party government took Ottawa to court over the carbon levy and the Appeal Court heard two days of hearings in February.
The ruling will come just weeks after Ontario was in court for its own legal challenge against the tax and Manitoba filed papers with the Federal Court to launch a case of its own.
Premier Scott Moe said in a statement Tuesday that he welcomes the court decision.
Saskatchewan is one of four provinces without a pollution reduction plan accepted by Ottawa that became subject to the federal tax April 1.
It was the first to take the matter to court, arguing the tax is not constitutional because it is not evenly applied across all jurisdictions.
A lawyer for the Attorney General of Canada suggested Ottawa does have the power to impose a price on carbon because greenhouse gas emissions are a national concern.
Another sixteen groups from across the country, including the provincial governments of Ontario, New Brunswick and British Columbia, intervened in the case.