Which Grade 11 & 12 Courses Matter Most for STEM Programs in Ontario?

If your teen is eyeing a STEM program at an Ontario university—whether that's engineering, computer science, life sciences, nursing, or anything in between—you've probably heard the phrase "prerequisite courses" thrown around a lot.

But here's what often gets lost in the conversation: not all prerequisites are created equal. Some courses are absolute deal-breakers that will close doors if not completed. Others are technically required but can sometimes be substituted or completed through summer school. And some courses, while not officially listed as prerequisites, are so heavily assumed by university programs that skipping them puts students at a serious disadvantage.

Confused yet? You're not alone.

The Ontario university application system can feel like navigating a maze blindfolded. Miss one turn in Grade 11, and suddenly your teen's options narrow significantly by Grade 12. Choose the wrong elective, and they might be scrambling to meet requirements at the last minute.

So let's clear this up. What courses actually matter for STEM programs in Ontario? Which ones are non-negotiable, and which ones give students flexibility? And how should families think about course planning in Grade 11 and 12 to keep as many doors open as possible?

The Core Four: Non-Negotiable for Almost Every STEM Program

Let's start with the big ones—the courses that show up on virtually every STEM program's prerequisite list. If your teen is serious about pursuing science, technology, engineering, or math at university, these are the absolute must-haves.

Grade 12 Calculus and Vectors (MCV4U)

This is the big one. If there's a single course that determines whether a student can pursue most STEM programs, it's Calculus and Vectors.

Nearly every engineering program requires it. Most computer science programs require it. Physics programs? Required. Many life sciences programs don't technically require it, but strongly recommend it—and students without it are often at a disadvantage in first-year coursework.

Here's the catch: to take MCV4U in Grade 12, students need to have completed Grade 11 Functions (MCR3U) in Grade 11. And to take Functions, they need Grade 10 Academic Math (MPM2D).

This means course planning for calculus actually starts in Grade 10, not Grade 12. Students who take Applied Math in Grade 10 or who struggle in Grade 11 Functions can find themselves locked out of calculus—and therefore locked out of many STEM programs—before they even realize what's happened.

Bottom line: If there's any possibility your teen wants to pursue STEM, they should be on the Academic/Advanced math pathway from Grade 10 onward, aiming to take Functions in Grade 11 and Calculus in Grade 12.

Grade 12 Advanced Functions (MHF4U)

Wait, didn't we just talk about math? Yes, but there are two Grade 12 math courses that STEM-bound students often need: Advanced Functions and Calculus and Vectors.

Advanced Functions focuses on polynomial, rational, exponential, logarithmic, and trigonometric functions. It's required for most engineering programs, many physical science programs, and some computer science programs.

Here's where it gets tricky: some schools offer Advanced Functions and Calculus simultaneously in Grade 12, while others require Advanced Functions first. This means students might need to double up on math in Grade 12 to meet requirements.

Talk to your school's guidance counselor early (ideally in Grade 11) to understand how these courses are sequenced and plan accordingly.

Grade 12 Chemistry (SCH4U)

Chemistry is the gatekeeper for life sciences, health sciences, engineering, and many physical science programs.

Want to study biology, biochemistry, neuroscience, or kinesiology? You need Grade 12 Chemistry. Nursing, pharmacy, or medicine down the road? Chemistry is essential. Engineering programs? Most require it.

The prerequisite for SCH4U is Grade 11 Chemistry (SCH3U), which in turn requires Grade 10 Academic Science (SNC2D). Students who take Applied Science in Grade 10 can still take Grade 11 Chemistry, but it requires more effort to bridge the gap.

Important note: Chemistry is cumulative. Concepts from Grade 11 directly inform Grade 12 content. Students who barely scrape through Grade 11 Chemistry often struggle significantly in Grade 12. If your teen found Grade 11 Chemistry challenging, getting support before starting Grade 12 Chemistry can make a huge difference.

Grade 12 Physics (SPH4U)

Physics is the other major science prerequisite for STEM programs, particularly engineering, physical sciences, and some computer science streams.

Not every STEM program requires Grade 12 Physics—life sciences students can often skip it—but for engineering and physics-heavy programs, it's non-negotiable. And like chemistry, Physics builds heavily on Grade 11 content (SPH3U).

Here's what students (and parents) often underestimate: Grade 12 Physics is hard. It's mathematically intensive, conceptually challenging, and moves at a fast pace. Students need a solid foundation in both Grade 11 Physics and Grade 11 Functions to succeed.

If your teen is considering engineering, taking Physics is a must. Even if it's not required, having it signals to admissions committees that the student is serious about STEM and prepared for the rigor of university coursework.

Beyond the Core: Strategic Course Selection

Alright, so those are the big four. But STEM-focused students often have room for one or two more science or math electives in Grade 11 and 12. Which ones make sense?

Grade 12 Biology (SBI4U)

Biology is required for life sciences, health sciences, and environmental programs. If your teen wants to study anything related to living systems—from microbiology to ecology to medicine—they need Biology.

The prerequisite is Grade 11 Biology (SBI3U), which is only offered at the University Preparation level. There's no Applied pathway in Grade 11, so students need to have taken Grade 10 Academic Science and performed well enough to move into university-level science courses.

Here's a strategic consideration: even if a program doesn't require Biology, taking it can strengthen an application. It shows breadth of scientific knowledge and demonstrates that the student can handle diverse STEM coursework.

Grade 11 and 12 English (ENG3U and ENG4U)

Wait, English? For STEM?

Yes. Every single Ontario university program—STEM or otherwise—requires Grade 12 English (ENG4U) as a prerequisite. There are zero exceptions.

This catches some STEM-focused students off guard. They load up on math and science courses and treat English as an afterthought, not realizing that a low English mark can sink their entire application.

Universities calculate admission averages differently depending on the program, but many STEM programs include English in the "top six" courses used for admission consideration. A 65% in English can pull down an otherwise stellar application.

Strategic advice: Don't neglect English. STEM students need strong communication skills anyway (university labs require lab reports, research requires writing, careers require clear documentation). Treating English seriously in Grade 11 and 12 pays off.

What About Data Management, Computer Science, and Other Electives?

Some students have room for additional math or science electives beyond the core requirements. Are they worth it?

Data Management (MDM4U)

Data Management covers probability, statistics, and data analysis. It's occasionally listed as an acceptable alternative to Calculus for certain programs (usually business or social science-related), but it's almost never sufficient for pure STEM programs.

If your teen has already taken or is planning to take Calculus, Data Management can be a useful elective—especially for students interested in fields like bioinformatics, epidemiology, or data science where statistics matters. But it shouldn't replace Calculus unless you've confirmed with specific programs that it's acceptable.

Computer Science (ICS3U and ICS4U)

Computer Science courses aren't often listed as formal prerequisites, even for computer science programs (ironic, right?). Universities assume students will learn programming in first year.

That said, taking high school Computer Science gives students a huge advantage. They enter university with coding experience, familiarity with logic and algorithms, and confidence in a field that intimidates many beginners.

If your teen is interested in computer science, software engineering, or any tech-related field, taking ICS3U in Grade 11 and ICS4U in Grade 12 is highly strategic—even if not required.

Earth and Space Science (SES4U)

This Grade 12 course explores geology, astronomy, and Earth systems. It's occasionally accepted as a science prerequisite for environmental science or geography programs, but it's rarely sufficient for mainstream STEM programs.

Unless your teen has a specific interest in geology or planetary science, Chemistry, Physics, and Biology take priority.

Course Planning Timeline: What to Take When

Here's a concrete roadmap for students aiming at STEM programs:

Grade 10

• Math: MPM2D (Academic Mathematics)

• Science: SNC2D (Academic Science)

This keeps all doors open. Taking Applied courses in Grade 10 doesn't close STEM pathways entirely, but it makes the Grade 11-12 journey significantly harder.

Grade 11

• Math: MCR3U (Functions)

• Sciences: Choose two or three from:

  • SCH3U (Chemistry) – essential for most STEM programs

  • SPH3U (Physics) – critical for engineering and physical sciences

  • SBI3U (Biology) – required for life sciences

• English: ENG3U

For maximum flexibility, taking all three sciences in Grade 11 is ideal (if schedules allow). This lets students keep all STEM options open going into Grade 12.

Grade 12

• Math: MHF4U (Advanced Functions) and MCV4U (Calculus and Vectors)

• Sciences: Choose from:

  • SCH4U (Chemistry)

  • SPH4U (Physics)

  • SBI4U (Biology)

• English: ENG4U

• Electives: ICS4U (Computer Science), MDM4U (Data Management), or other interests

The specific sciences depend on program goals, but Chemistry is almost always a safe bet.

Common Course Planning Mistakes (And How to Avoid Them)

Even with good intentions, families make predictable mistakes when planning high school courses. Here are the big ones:

Waiting Until Grade 12 to Think About Prerequisites

By Grade 12, students are locked into the pathways they chose in Grade 10 and 11. If they didn't take Academic Math in Grade 10, they can't take Calculus in Grade 12 without summer school or night school catch-up.

Solution: Start researching program requirements in Grade 10, not Grade 12. Understand the prerequisite chains early so you're not scrambling later.

Assuming "Science" Is One Thing

Many parents think "my kid is taking science" without realizing that universities differentiate heavily between Chemistry, Physics, and Biology. A student who takes only Biology in Grade 11 and 12 can't apply to engineering programs—no matter how high their Biology mark is.

Solution: Look at specific program requirements for universities your teen is interested in. Know which sciences are required, recommended, or optional.

Prioritizing Interest Over Strategy

It's great that your teen loves Biology and hates Physics. But if they want to study biomedical engineering, they need Physics—whether they love it or not.

Solution: Balance interest with pragmatism. Encourage students to take courses that keep doors open, even if they're not their favorite. They can specialize later.

Not Planning for Doubled Math Courses

Some programs require both Advanced Functions and Calculus. Some schools offer them simultaneously; others require taking one before the other. If students don't plan for this, they might have to take summer school math or drop another course to fit them both in.

Solution: Meet with guidance counselors in Grade 11 to map out the Grade 12 schedule and ensure math courses align with university requirements.

Assuming "Recommended" Means "Optional"

When a program says a course is "recommended but not required," many students skip it. But here's the reality: "recommended" often means "you'll struggle without it."

For example, some life sciences programs don't require Calculus, but they recommend it. Students who skip Calculus might meet the admission requirements, but they'll hit a wall in first-year courses that assume calculus knowledge.

Solution: Take "recommended" seriously. If a program recommends a course, there's usually a good reason. Skipping it might get you admitted, but it can hurt your success once you're there.

What If Your Teen Is Behind or Unsure?

Not every student follows the "ideal" STEM pathway perfectly. Life happens. Interests change. Students switch from Applied to Academic streams, or realize in Grade 11 that they want to pursue STEM when they previously didn't.

If your teen is behind on prerequisites, here are options:

Summer School: Many school boards offer Grade 11 and 12 courses over the summer. Students can use this to catch up on Functions, Chemistry, or other prerequisites.

Night School or Online Courses: Some students take night classes or online courses through organizations like ILC (Independent Learning Centre) to complete prerequisites while still in high school.

Fifth Year / Victory Lap: Some students stay in high school for a fifth year to complete prerequisites they missed, upgrade marks, or strengthen their university applications.

Alternative Pathways: Community college science programs often have less stringent high school prerequisites. Students can complete a college diploma and then transfer to university, or they can use college as a stepping stone to build their science foundation.

None of these paths are ideal, but they're all viable. The key is to identify gaps early and make a plan—not to ignore the problem and hope it resolves itself.

Final Takeaway

Course planning for STEM programs isn't something you can wing. The decisions students make in Grade 10 and 11 directly impact which programs they can apply to in Grade 12. And once doors close, reopening them requires extra time, money, and effort.

The good news? With early planning and strategic course selection, students can keep their options wide open. They can explore different STEM fields, discover new interests, and enter university prepared for the rigor of first-year STEM coursework.

And if your teen does fall behind or struggles in a prerequisite course, there are ways to catch up—especially with the right support.

The goal isn't to push students into STEM if it's not right for them. The goal is to make sure that when they're ready to make that choice, they've kept the door open.

👉 If your teen is navigating prerequisite courses and could use academic support to succeed in Math, Chemistry, Physics, or English, we'd love to help. Our graduate-level tutors specialize in helping students build strong foundations in STEM subjects. Request a tutor or book a consultation to discuss how we can support your student's path to university.