Cornerstone College is an independent, Lutheran, co-educational, secondary, day school, located at Mount Barker in the Adelaide Hills south-east of Adelaide, South Australia.

The College is a non-selective school, currently catering for approximately 864 students from Years 7 to 12.

Facilities include a library, a basketball court, gymnasium, a canteen, an oval and a theatre.

[5] Cornerstone was established in 1990 as the first Christian secondary school in the Adelaide Hills area, having been first proposed in 1984.

In 2014, the college introduced year 7's to the grounds under a plan made in 2010 by former principal John Proeve.