Young people will be asked to wear face coverings, unless they are exempt.
Young people exempt from wearing face coverings include anyone who cannot put on, wear or remove a face covering because of a physical or mental illness or impairment, or disability.
Anyone speaking to or providing assistance to someone who relies on lip reading, clear sound or facial expression to communicate is also exempt.
Cases of Coronavirus in Dorset are lower than many other parts of England.
Cllr Andrew Parry, Dorset Council Portfolio Holder for Children, Education and Early Help, said: “We continue to monitor and review the situation in order to minimise any potential risk. As a result we are asking secondary and upper school students in Dorset to wear a face covering on school transport from Monday unless they are exempt.
“This is to keep everyone safe and reassure drivers. Our message to our young people is thank you for wearing a face covering to protect yourself and others.”