Hills Adventist College is an independent Seventh-day Adventist co-educational early learning, primary and secondary day school, located across two campuses in Sydney's Hills District, New South Wales, Australia. Enrolments at the College during 2016 totalled 566 students. The junior school, comprising an early learning centre and teaching facilities for students in Year K to Year 4 is located in Castle Hill; and the senior school, comprising teaching facilities for students in Year K and Year 5 to Year 12, is located in Kellyville. The College is a part of the Seventh-day Adventist education system, the world's second largest Christian school system.