How Long To Grill Squash And Zucchini In Foil

Grilling squash and zucchini in foil usually takes about 15 to 20 minutes over medium heat, depending on how thick you slice them.
 
If you’re wondering how long to grill squash and zucchini in foil, the short answer is roughly 15 minutes for thin rounds and closer to 20 minutes for thicker spears or halves.
 
Foil packets trap steam and heat, so your veggies cook faster than if you tossed them directly on the grates.
 
That means you get tender squash and zucchini with minimal fuss and almost no cleanup.
 
In this post, we’ll walk through exactly how long to grill squash and zucchini in foil, plus a few tips to nail the texture and flavor every single time.
 
Let’s get grilling.
 

How Long to Grill Squash and Zucchini in Foil

The timing for grilling squash and zucchini in foil depends on a few things, but here’s the general range you can count on.
 
Most foil packet recipes call for 15 to 20 minutes on a covered grill at medium heat, which is around 350°F to 400°F.
 
If you slice your squash and zucchini into quarter-inch rounds, they’ll be tender in about 15 minutes.
 
Thicker slices or spears need closer to 20 minutes, and whole small zucchini can take 25 minutes or more.
 
The key is to check them a few minutes before your target time so they don’t turn to mush.
 
You want them fork-tender but not falling apart, with a little bite still left in the center.
 

1. Thin Rounds Cook in About 15 Minutes

When you grill squash and zucchini in foil as thin rounds, they cook fast because there’s more surface area exposed to the steam inside the packet.
 
A quarter-inch slice typically hits perfect tenderness right around the 15-minute mark.
 
This is the timing I use most often for weeknight dinners because it’s quick and reliable.
 

2. Thicker Spears Need Closer to 20 Minutes

If you cut your squash and zucchini into spears or half-inch slices, plan on about 20 minutes.
 
The extra thickness means heat has to travel further to the center, so give them a few more minutes on the grill.
 
Spears also hold their shape better, which is nice if you’re serving them as a side dish.
 

3. Whole or Halved Squash Takes 25 Minutes or More

Grilling whole squash and zucchini in foil takes the longest, often 25 to 30 minutes.
 
The skin acts as a barrier, so the steam has to work harder to soften the flesh inside.
 
I usually halve them lengthwise and scoop out the seeds first, which cuts the time down a bit.
 

Factors That Affect Grilling Time in Foil

How long to grill squash and zucchini in foil isn’t just about the clock.
 
Several variables can push your cook time up or down, and knowing them helps you adjust on the fly.
 

1. Grill Temperature

Medium heat, around 350°F to 400°F, is the sweet spot for grilling squash and zucchini in foil.
 
Go hotter and the outside may scorch before the inside softens.
 
Go cooler and you’ll be waiting 30 minutes or more for tender veggies.
 

2. Foil Packet Size and Seal

A tightly sealed foil packet traps steam, which speeds up cooking.
 
If your packet is loose or has gaps, heat escapes and your squash and zucchini take longer to grill.
 
I always fold the edges twice to lock in that steam.
 

3. Slice Thickness and Variety

Zucchini tends to cook a little faster than yellow squash because it has more water content.
 
Thin slices of either will always beat thick chunks in the race to tenderness.
 
So keep your pieces uniform if you want everything to finish at the same time.
 

Tips for Perfect Foil-Grilled Squash and Zucchini

Now that you know how long to grill squash and zucchini in foil, here are a few tricks to make them taste amazing.
 

1. Don’t Skip the Oil and Seasoning

Toss your squash and zucchini with olive oil, salt, pepper, and garlic powder before sealing the foil.
 
The oil helps them roast instead of steam, giving you better flavor and a little caramelization.
 
A squeeze of lemon juice at the end brightens everything up.
 

2. Add a Pat of Butter for Richness

A small pat of butter inside the packet melts into a silky sauce that coats every slice.
 
It’s a simple upgrade that makes grilled squash and zucchini in foil taste like a restaurant side.
 
Just don’t overdo it or the veggies get greasy.
 

3. Leave Room for Steam to Circulate

Don’t cram the foil packet too full.
 
Leave a little space so steam can move around the squash and zucchini and cook them evenly.
 
If you’re feeding a crowd, make two smaller packets instead of one giant one.
 

4. Rest Before Opening the Foil

Once you pull the packet off the grill, let it sit for two or three minutes.
 
The residual heat finishes the cooking and the flavors settle.
 
Then carefully open the foil away from your face to avoid a steam burn.
 

So, How Long to Grill Squash and Zucchini in Foil?

Grilling squash and zucchini in foil takes about 15 to 20 minutes over medium heat, with thin rounds finishing fastest and thicker cuts needing a few extra minutes.
 
Foil packets trap steam and heat, so your veggies cook quickly and evenly with almost no cleanup.
 
Just remember to seal the foil tight, season well, and check a few minutes early so they don’t turn mushy.
 
Whether you’re grilling squash and zucchini in foil for a quick weeknight side or a backyard cookout, this method delivers tender, flavorful results every time.
 
Now fire up that grill and enjoy.