This school was established in BS 2036(1980 AD) as a Pre-Primary School in Kalikanagar, Butwal-12, Lumbini, Nepal. Those days there were very few private schools in this area. Siddhartha was one of the pioneers in this field.But it was BS 2050(1993 AD) when Siddhartha English Boarding Secondary School revived. A new set of team, consisting only teachers and academicians, took-over. Till then most of the school was run by an individual in very limited area. The team envisioned a school with ample space and all amenities in a congenial milieu.The school was recognized as the High School the same year by the Government of Nepal. Initially there were about 300 students. There were only ten students in the first batch who appeared SLC (School Leaving Certificate) Examination, the national exam that is taken at the end of class 10, from this school. Since then, school has not turned back. Every year the strength of the school went on increasing and now there are about 2000 students in this institution. This would not have been possible without incorporating the constructive suggestions from our guardians, well wishers and incessant hard work of the teachers. We express our gratitude to them.
The school launched ‘Plus Two’ program under the then HSEB (Higher Secondary Education) in the year B.S. -2071(2014 A.D.). Now it offers Science and Management streams in classes XI and XII under N.E.B (National Education Board).