St. John's High School (SJHS) is a senior high school in Charleston, South Carolina, on Johns Island.

St. John's is home to approximately 300 students and 30 faculty and staff.

[3] St. John's offers Advanced Placement and dual credit courses totaling over 30 hours of offered college credit, as well as three career academies in Hospitality and Tourism, Computer Science, and Culinary Arts.

St. John's competes at the A level in football, volleyball, basketball (boys' and girls'), wrestling, soccer, track, baseball, and softball.

The Islanders also offer marching band, agriculture and green house, weightlifting, competitive academic team, and student council.