The rail operator had warned ongoing negotiations meant that drivers were not volunteering for Sunday shifts.
ScotRail said it aimed to run two-thirds of its services and buses would replace trains on some routes.
The operator has published an amended timetable listing cancelled services and those with reduced frequency.
On Wednesday, ScotRail said it had offered drivers a 2.5% pay rise and a one-off bonus, and would increase driver numbers.
But Aslef accused the Abellio-owned operator of trying to push new terms and conditions through.
Scottish Trades Union Congress general secretary Grahame Smith said: "It is simply astonishing that significant service reductions are being announced only three months after Abellio assumed control of the ScotRail franchise.
"Their approach to workforce planning and industrial relations appears nothing short of shambolic and contrary to the impression they were anxious to portray during the bid process.
"The Scottish government must now answer serious questions over how service cuts and amateur industrial relations are permissible under the terms of a very detailed franchise agreement."
A Transport Scotland spokeswoman said: "Industrial relations are a matter for the employer and the union.
"It is in the best interests of passengers that ScotRail and Aslef come together to resolve this issue as quickly as possible to avoid unnecessary disruption.
"Keeping passengers informed and ensuring they can plan ahead with confidence in advance is a key priority and people should check the updated timetables on the ScotRail website before they start their journey."
ScotRail have said that although they will be running fewer trains on Sundays, most of the trains that do run will have more carriages.
It claimed this would provide almost the same capacity as was offered by the normal services on every route.
The rail operator has advised customers to plan ahead for the weekend.

The Transforming British Tennis Together initiative aims to make the sport more accessible.
Over the next 10 years, it will raise the number of covered and floodlit courts by 50%, refurbish facilities and make courts easier to book online.
The LTA's Alastair Marks said: "We're focused on getting the next generation of players on court and having fun."
Get Inspired: LTA's £250m for better tennis access
The governing body will invest £125m to improve existing community facilities and is hoping to source a further £125m through matched funding.
Only 7% of Britain's 23,000 courts have covers and one in seven park courts have floodlights.
With the new funding, the LTA aims to deliver:
The initiative has been tried out on a trial basis in 10 towns and cities, including Sheffield, where £1.5m was invested and has increased the number of people playing tennis by 54% over the last three years.
Marks, participation director at the LTA, added: "There's never been a better time to invest in making our tennis courts the social hubs of their communities once again."
Clubs and communities can register their interest in bidding for the funding here.

Spokesman Josh Earnest confirmed a private party was held on Saturday but said little else.
The guest list of 500 was said to include lobbyists, CEOs and celebrities.
The Rev Al Sharpton tweeted about a performance by Prince and Steve Wonder.
The civil rights activist and TV host wrote it was "awesome" to see them both on the keyboards.
Mr Earnest did say the Obamas' paid for the party on "their own dime", but would not say how much the party cost.
The New York Post reported that film director Tyler Perry, actresses Angela Bassett and fashion designer Naeem Khan were among the celebrity guests.
ScotRail has cancelled a third of its usual services this Sunday, after pay talks with train drivers' union Aslef stalled.
[NEXT_CONCEPT]
The Lawn Tennis Association (LTA) is leading a £250m investment to improve grassroots facilities.
[NEXT_CONCEPT]
White House officials will not say whether pop star Prince performed at a weekend party at the executive residence despite guests posting about it on social media.