St. Mary's High School, Mount Abu was established in 1887 and handed over to the Congregation of Christian Brothers in India in 1929. It is one of the many Edmund Rice Institutions in India managed by the Christian Brothers. The CCBI is a registered Society under the Society Registration Act and has its Head Office at New Delhi.

In 1887 it was known as Mount Abu Railway School (MARS) was designed by Mr. Blood, Engineer in Chief of BB & CI Railway. The School was Primarily for children of European and Anglo-Indian Railway Staff. In 1902 it was known as Abu High School, a private Institution no longer under the Railways. In 1929 Irish Christian Brothers took over. Brs. G.A.Cooney, J.S. Jokim and P.C. Hart began classes on March 04 with 19 Boarders and 03 Day-Scholars.

Our Motto – “PROMITE VIRES” (Latin Word) which means “PUT FORTH THY STRENGTH”