Grantham Academy, built in 1829, was a direct precursor to St. Catharines Collegiate.

The institution was funded by William Hamilton Merritt.

The current building in which St. Catharines Collegiate stands was completed in 1923, causing the school to celebrate its hundredth anniversary in 2023.

[3] The school has a co-op program where students can learn culinary skills.

[5] In 2024, a school employee was charged with sexual assault of a 16 year old student.