The Illawarra Grammar School, abbreviated as TIGS or Illawarra Grammar, is an independent Anglican comprehensive co-educational early learning, primary and secondary day school, located at Mangerton in the Illawarra region of New South Wales, Australia.

The school caters for approximately 1,100 students from early learning to Year 12.

TIGS offers an early learning program for students between 3 and 5 years of age called TIGS Prep (previously titled, The Piper Centre).

[2] The Illawarra Grammar School was founded in 1958 by Bishop Gordon Begbie and dedicated parents.

[4] At the end of 2018, TIGS announced the appointment of the eighth Principal, Judith Nealy, as the successor for long-serving Headmaster, Stephen Kinsella.