City Hall will relax regulations to allow students enrolled in 437 schools under its supervision to don casual wear once a week, says deputy Bangkok governor Sanont Wangsangboon.
The relaxed rules for uniforms will also apply to scouts. Looser rules for hairstyles are likewise planned in the City Hall announcement.
However, Mr Sanont said the details are still being examined by City Hall's legal team to ensure they do not clash with education ministry directives.
It is not clear which will take precedence in the event the two can't be reconciled.
He expects the announcement to be published in two weeks.
The deputy governor discussed the proposals on Saturday during a speech on youth and political participation at Thammasat University's Tha Prachan campus.
Children's rights advocates have argued against strict regulations governing students' hairstyles and the school dress code.
Many advocates view the uniform rule as an infringement of students' human rights.
Many propose that school guidelines be revised to reflect present trends. Schools enforcing strict hairstyle rules have also come under fire.
Mr Sanont also said City Hall attaches importance to diversity in regard to learning and plans to encourage discussions about the matter and promote learning beyond the classroom.
More often than not, learning takes place outside classrooms, he said -- and in his view coffee shops can also be a learning place, just like universities.
However, openness to diversity is crucial to encourage learning among students.
"Today is an important day for youth, and the issue should be discussed more," he said. "Bangkok is a place of diversity, and universities are open spaces for it.
"Bangkok has 437 schools, 34 libraries, local museums and more under its jurisdiction," he said.
"These areas aren't just for studying only," he said.
"As Bangkok governor Chadchart Sittipunt always stresses: 'Education isn't as important as learning.'"
Earlier, Mr Chadchart criticised the Interior Ministry's order to have provinces hand out scout uniforms to boys and girls, saying while the order was meant to ease the financial burden of parents, it must not create financial constraints for City Hall.