Leicester's goalkeeper coach Mike Stowell and coach Chris Powell will be joint caretaker managers against the Iron at the Walkers Stadium on Saturday afternoon.
Sousa only took charge at the Foxes in the summer - leaving Swansea to replace the Hull-bound Nigel Pearson - but has been told to leave with the club bottom of the table after their first nine games.
"To be sacked after being told that there was a long term strategy at the club and after only nine games in charge is something that I find very surprising," he said.
Leicester hope to appoint a manager quickly after the game against the Iron. Sven-Goran Eriksson, the former England and Manchester City boss, has been installed as favourite.
"The club would like to state that Paulo Sousa is a first-class individual, but that this decision has been taken in the best interests of the club and our ambitions to move up the Championship," read a statement from Leicester.
"The search for a new manager begins immediately and the club anticipates a quick appointment."
The decision to sack Sousa drew criticism from Richard Bevan, chief executive of the League Managers Association.
"Knee-jerk dismissals, and the chopping and changing of managers will not deliver success on the field and is incredibly destabilising to the entire club," he said.
"Paulo's sacking is even more disappointing in light of the chairman's comments on Paulo's appointment, in the summer, when he stated he was 'delighted to acquire a manager of such great calibre'.
"Leicester City Football Club has had 14 managers since 2004 and six whilw the current chairman has been at the club. Clearly the club has to examine its manager recruitment strategy as their current approach does not work. It is damaging to the club and its fans and is an inappropriate way to treat talented managers and their careers."