Island Trees High School is a coeducational public high school serving students in ninth grade through twelfth grade, in Levittown, New York, United States, 31.0 miles east of Manhattan.

It is a part of the Island Trees Union Free School District.

The school offers various clubs, electives, and AP courses.

Island Trees High School serves portions of Levittown, Bethpage and Seaford.

As of the 2016–17 school year, the school had an enrollment of 746 students and 59 classroom teachers (on a full-time equivalent basis), for a student–teacher ratio of 12.74:1.