Countryside High School, also known as CHS, is a public high school located in Clearwater, Florida. Established in 1980, it is a part of the Pinellas County Schools system, and is one of the larger schools in Pinellas County. It draws students from Dunedin, suburban east Clearwater, Safety Harbor, and Oldsmar.

Countryside High School is one of the largest and most prestigious schools in the Pinellas County School system.

The school's first graduating class in 1980 finished before the school was completed and held classes and graduation at Dunedin High School.

Countryside High School's Battle of the Books Team took First Place in the Battle of the Books for three years running, beginning in 2010.

In 2022 a resurfaced outside facade and a new mall floor design were built.

The school offers numerous advanced academic programs and recognition, including foreign languages and technology honor societies along with ISTEM (institute of science, technology, engineering and mathematics), and CCT (Center for Computer Technologies). The Winter guard is the Scholastic Class A Florida Federation of Color guard Circuit (FFCC) state champions and the scholastic class A Winter Guard International bronze medalists in 2006.

The school won the first high school "Battle of the Books" competition in 2006, repeating the feat again in 2007, 2008, 2011, 2012, 2013, 2015.

The school newspaper, Paw Print, has received an All Florida Rating from the Florida Scholastic Press Association; a Superior from the Southern Interscholastic Press Association and an International Second Place Award from Quill and Scroll.^{[citation needed]}