More than 50 pupils were sent home from lessons after turning up for school wearing inappropriate footwear - including flip-flops.
The headteacher of Djanogly City Academy defended teachers' actions and said being properly dressed was an important life lesson for children.
About 100 pupils who broke the school's uniform rules are reported to have been taken out of class on the first day of term yesterday, with 56 sent home to change after their parents were contacted.
The uniform policy states plain black leather shoes should be worn by the 1,197 pupils on the roll.
The Nottingham academy has been in special measures since 2013.
However, the school been steadily improving under the stewardship of new head Dave Hooker.
Mr Hooker said: "Being appropriately dressed, whether for school or work, is a lesson that will benefit all our students throughout their lives.
"It is our duty to give them every advantage and a key part of that is understanding that personal standards are very important."