Park Street Collegiate Institute (PSCI) was a secondary school located in Orillia, Ontario, Canada.

It was built in 1961 to help with the overflow of students from Orillia District Collegiate & Vocational Institute.

In March 2008, a review process was to have begun to consolidate Orillia's three public high schools into two buildings as a result of cost of maintenance of the aging buildings and the declining enrolment at PSCI.

[3] On 28 November 2007, a bomb threat written on a mirror in a student washroom caused great concern and students were kept in classes in a school lockdown for the morning as police cleared the building room by room.

Nothing suspicious was found and students returned to classes following an extended lunch break.