Despite this decline, St. Theresa Catholic Secondary School's score was still above the provincial average.

[8] From 2011 to 2015, STCSS' score fell by 2.9 points, marking an era of academic decline in the 2010s.

It scored 5.6/10 and ranked 477th out of 747 Ontario secondary schools, still well below the provincial average of around 6.0.

STCSS remained the only secondary school in the ALCDSB to rank below the provincial average.

To accommodate the growing student population, a new wing was constructed and officially opened during the 2005 school year.

This expansion included a new art studio, updated office spaces, and a dedicated life skills room.

[19] St. Theresa also has a number of off-campus classrooms that it shares with Sir James Whitney School, where welding, mechanics, cosmetology and construction programs are taught.

[20] St. Theresa Catholic Secondary School offers a range of sports for students, including curling, hockey, soccer, rugby, golf, swimming, alpine and downhill skiing, cross-country running, track and field, ultimate frisbee, basketball, baseball, volleyball, badminton, and tennis.