A Complete Guide to OSSD Course Selection from Grades 9 to 12

Earning the Ontario Secondary School Diploma (OSSD) requires 30 credits (18 compulsory + 12 electives; for students entering from 2024 onward, 17 compulsory + 13 electives), passing the Ontario Secondary School Literacy Test (OSSLT), and completing 40 hours of community service. University admission mainly looks at the best 6 Grade 12 U/M-level courses (the "Top 6") — so course selection in Grades 9–11 is essentially about building the right "prerequisites" for Grade 12.

Grades 9–10: Build the foundation, leave room to explore

• Core strategy: Complete most compulsory courses; stay on the Academic pathway (Ontario moved Grade 9 to De-streamed starting in 2026). Don't drop into Applied-level courses blindly — keep your university pathway open.

• Course focus: The compulsory English (ENG), math (MPM), science (SNC), and history/geography in Grades 9–10, plus arts and physical education electives.

Grades 11–12: Plan by university program

To apply successfully to competitive programs, you must take the right core prerequisite courses in Grade 12. Here are the classic course combinations by field:

• Engineering

  • Grade 12 Top 6: ENG4U (English) + MHF4U (Advanced Functions) + MCV4U (Calculus and Vectors) + SCH4U (Chemistry) + SPH4U (Physics) + any 1 U/M course.

  • Suggestion: Finish all 3U sciences (physics, chemistry) and 3U math in Grade 11 — the pace is tight.

• Computer Science & AI

  • Grade 12 Top 6: ENG4U + MHF4U + MCV4U + SPH4U (required by some top universities) + ICS4U (Computer Science, strongly recommended) + any 1–2 U/M courses.

  • Suggestion: Take ICS3U early in Grade 11, and strengthen math/logic in Grades 11–12 (e.g., MDM4U Data Management as a supplement).

• Business / Commerce

  • Grade 12 Top 6: ENG4U + MHF4U + MCV4U (required by most top business schools, such as Rotman and Ivey) + any 3 U/M courses (e.g., BAT4M Accounting, BBB4M International Business, ECO4U Economics).

  • Suggestion: Keep a balanced arts-and-science profile, maintain a high GPA in Grade 12, and use business electives to demonstrate business interest.

• Sciences (Biology / Chemistry / Environment, etc.)

  • Grade 12 Top 6: ENG4U + MHF4U + MCV4U (or MDM4U) + 2 science courses (SBI4U Biology / SCH4U Chemistry / SPH4U Physics) + any 1 U/M course.

  • Suggestion: For Life Sciences / Life Medicine, biology + chemistry is the must-have combination.

• Social Sciences & Humanities

  • Grade 12 Top 6: ENG4U (a high mark here is critical) + any 5 U/M courses (recommended: MDM4U Data Management, HSB4U Challenge and Change in Society, EWC4U The Writer's Craft, history/law courses).

  • Suggestion: There is no hard science requirement, but taking MDM4U (Data Management) is very helpful for social science research and statistical analysis at university.

• Arts & Design

  • Grade 12 Top 6: ENG4U + any 5 U/M arts or humanities courses (e.g., AVI4M Visual Arts, ASM4M Media Arts).

  • Suggestion: Grades only need to meet the bar — the real focus should be on the portfolio in Grades 11–12.

Pitfall guide: avoid these course-selection traps

1. Watch the prerequisite chain: Grade 12 Calculus (MCV4U) requires Grade 12 Advanced Functions (MHF4U) as a prerequisite, which in turn requires Grade 11 math (MCR3U). One wrong step, and you may not be able to take the courses that follow.

2. Read the course codes: For university admission, the fifth character of the course code must be U (University) or M (University/College). Courses with C or P/O don't count toward the Top 6 admission average.

Closing

Course selection is a four-year chess game — every choice in Grade 9 either opens or closes a door in Grade 12. The earlier the plan, the fewer the regrets.

Before choosing courses, ask one question: do I know exactly which Grade 12 prerequisites my target university programs require?