Two students attached to the Hegalla Vidyalaya, Kosgoda were injured and admitted to the Balapitiya hospital following a clash between students in the Grade 11 class, on Tuesday.
The two students were identified as Vihanga Sathsara and Roshan Yonal of Kosgoda.
Hospital sources said one of the injured students had undergone surgery.
Kosgoda Police said the students were injured following a stabbing incident. Investigations are continuing to apprehend the student responsible for the stabbing.