Dundee Utd sack manager Ross after 9-0 loss to Celtic
Stay tuned with 24 News HD Android App
The former Alloa, St Mirren, Sunderland and Hibernian manager's reign at Tannadice lasted just seven games in charge.
United's humiliating reverse by Scottish champions Celtic on Sunday was their fifth consecutive defeat and meant they had conceded 23 goals in their last four games.
"Dundee United can confirm head coach Jack Ross has been relieved of his duties with immediate effect," said a club statement.
"Liam Fox will take charge of the the first team on an interim basis with the focus now fully on Wednesday's Premier Sports Cup match with Livingston."
Ross was appointed on June 20 after Tam Courts moved to join Hungarian club Honved.
The 46-year-old Ross's first match in charge of United was a Premiership draw with Kilmarnock and he then oversaw a 1-0 Europa Conference League win over AZ Alkmaar at Tannadice.
But results rapidly went downhill after that win, with a 1-0 home defeat by Livingston followed by a 7-0 loss away to Dutch club Alkmaar that equalled the worst result by a Scottish club in European competition.
Ross, speaking after Sunday's thrashing by Celtic, signalled his determination to get United back on an even keel.
"Regardless of what club I'm at or what level I had the same burn to do well as a manager at Alloa as I do now," he said.
"And because of the embarrassment and humiliation I feel right now then, absolutely, I want to put that right."
Ross's departure from Dundee United was announced on the same day as English Premier League club Bournemouth sacked boss Scott Parker following a 9-0 defeat by Liverpool last weekend.