Grassdale High was established in 1983, under the name Grassy Park No. 2 Senior Secondary School.

The first principal of the school was Mr. B. Europe with Mr. T. Jardine as his deputy. The first twelve educators at the school included:

H. Adriaan (Science), C. Adriaans (Accountancy), F. Enous and D. Forbes (English), T. Jardine and F. Kennel (Afrikaans), M. Galant (History/Geography), E. Manasse (Needlework), M. Mora/Cupido (Home Economics), O. Moses (Woodwork), J. September (Afrikaans/Geography), M. Williams (Mathematics/Music), with H. Sedras as secretary.

In 1983 the school consisted of eight standard six classes (Grade 8) and one standard seven class (Grade 9). The school grew rapidly and by 1987 had 54 teachers. We had our first matriculants in 1986.

In 1985 the school officially became Grassdale High School – named after an educationist. Grassdale High has had five principals since its inception namely:

  1. B. Europe (1983 – 1984)
  2. F. Kennel (1985 – 1993)
  3. C. Saulse (1994)
  4. S. Cupido (1995 – 2012)
  5. D. Tregonning (2013 - Present)

Grassdale has always emphasized the importance of being well educated, hence its motto Scientia Illuminat – Knowledge Enlightens. Learners are encouraged to be courteous, honest, respectful and caring. We at Grassdale believe that these are the values needed to be successful in life. We also believe that if our learners cannot be the best they must be amongst the best. As a result of this the school has a proud academic record. Our matriculants of 2011 have done themselves, their parents and the school proud by obtaining a 98.6% pass rate in the NSC examinations. This achievement elevated Grassdale High to being the best performing school in Circuit 3 for 2011. Learners are reminded that your background should not limit your progress.

There are many challenges facing Grassdale High but if we can build on the firm foundation on which the school was founded we can go into the future with confidence.