Hammarskjold High School is one of 4 high schools in the Lakehead District School Board in Thunder Bay, Ontario. Hammarskjold High School consists of 65 teachers and approximately 760 students. The school is named after Dag Hjalmar Agne Carl Hammarskjold, a Swedish statesman who served as the second Secretary-General of the United Nations. The success of students who have attended Hammarskjold over the past 50 years has established a reputation of academic and extra-curricular excellence.

Hammarskjold offers a full range of secondary programs to address the needs of all career pathways and post secondary destinations: university, college, apprenticeship, or work. Hammarskjold offers the widest selection of language courses in the Lakehead District School Board, and the greatest diversity in the arts area of any school in the region.