Kong Yiong High School (1986)
Guangyang Secondary School has its humble origins in Kong Yiong High School which was located at Yio Chu Kang Road. However, in 1986, Kong Yiong High School was closed due to a sharp drop in school enrolment.
Guangyang Secondary School (1987–2005)
In 1987, the School Advisory Committee of Kong Yong High School left a sum of about $60,000 which was to be given to a school that adopted its name. While the new school was being set up in Bishan, it was decided that the old dialect name "Kong Yong" be used. Hence, the new school came to be known as "Guangyang" which is the Hanyu pinyin equivalent of "Kong Yong". Thus, Guangyang, Secondary, a government English medium school, was set up. In its early months, Guangyang Secondary shared the premises of Zhonghua Secondary School.
The new school, costing $7 million, is a modern complex with excellent facilities. It had 28 classrooms, a library, an audio-visual theatrette, six science laboratories, two home economic rooms, an EOA room, four computer laboratory, an IT-enabled resource room, two technical workshops, a football field, a basketball court and a volleyball court (which has been converted into a street soccer court), and an indoor sports hall (shared with Guangyang Primary School). The school was officially opened on 27 June 1990 under the helm of her first Principal, Mr Leong Khin See. The school had her second Principal when Mrs Alice Tan Lee Huan assumed her position in 1993. Guangyang Secondary School achieved the distinction of being one of the Top 18 Value-Added Schools in the Special/Express stream. The school's third Principal, Mrs Ng-Ong Phiak Kim then took over since mid-December 1996. The school was ranked as one of the Top 20 Value-Added Schools in the Special/Express Stream for consecutive 2 years. Guangyang ushers in the new year 2001 with her fourth Principal, Mrs Ngiam Geak Kim. Mrs Ngiam assumes the position from 1 January 2001. She retired that same year. Miss Low Chee Moon took office as Guangyang Secondary School’s fifth Principal in 2002.
In December 2002, the school undergoes PRIME and was temporarily shifted to Toa Payoh so that rebuilding could take place at its present site.
Merging with Braddell-Westlake Secondary School (2006)
In 2003, Ministry of Education (MOE) announced that Guangyang Secondary School and Braddell-Westlake Secondary School will merge in 2006. The secondary one cohorts of both schools collaborated to produce a ceramic mural wall that will be installed in the new merged school in early 2005. In June 2003, Guangyang Secondary returned to its Bishan Campus. The school was presented Value-Added Award (Bronze) for its commendable performance in the 2004 GCE O Level Examination. Guangyang Secondary School and Braddell-Westlake Secondary merged in 2006 and Mrs Tan Miao Ling took over as the school's sixth Principal. Guangyang Secondary’s name is retained. Mr Benjamin Kwok took office as Guangyang Secondary School’s seventh Principal in December 2012.