The Education Ministry has left schools to make up their own minds about the hairstyles required for pupils, the Education Minister said on Wednesday.
Education Minister Trinuch Thienthong said each school had been given the freedom to come up with the hairstyle rules deemed suitable for students.
The ministry did not impose a specific hairstyle for students and instead gave all schools flexibility on the issue by settling on an appropriate style with parents and students, she added.
Ms Trinuch said schools had been ordered not to use harsh punishment on students who break hairstyle rules.
The so-called Bad Student movement continued to urge the government to end hairstyle regulations. Their members posted the #freehairstyles banner outside several schools on Monday on the eve of the new term.
The ministry lifted regulations governing student hairstyles for both boys and girls in 2020 but still left room for teachers to interpret them as they wished.
According to the current ministry regulation, student hairstyles must be appropriate as deemed by school directors.
The Bad Student group has argued that some schools were ignoring the regulation and still forced students to keep very short haircuts.
Early this month, toiletries company Dove also launched a campaign against forced haircuts that became popular on social media.