Sekolah Menengah Seri Mahawangs a was established on the 1st April 1970. Initially it was known as Sekolah Menengah Jitra II with a population of 200 students. The first principal was Mr Boonlert Somchit.
In the following year, the number of students increased to 500 and in the third year it increased further to 700. To accommodate the large students population , the school had to use classes at nearby Sekolah Rendah Jenis Kebangsaan Chong Hwa (Chong Hwa National Type Primary School) and Sekolah Menengah Pulau Nyior (Pulau Nyior Secondary School).
In 1973, the school changed its name to Sekolah Menengah Seri Mahawangsa which means ‘The Light of Greatest Race’. The name ‘Mahawangsa’ was inspired by the second principal Mr Koong Swee Kee.