About 700 unionized employees have been without a contract since the end of 2012 and are hoping the strike forces management back to the bargaining table.
They say wages are the main sticking point in the negotiations.
The provincial park website says all 22 parks in the system are still open and campground reservations will be honoured.
But it says that some services could be disrupted, such as equipment rentals.
The government is offering a four per cent hike over five years, while the union wants an increase that goes up at least as much as inflation.
Workers in Quebec's provincial park system, known as SEPAQ, make an average of $14 an hour.