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Since I've shared a lot of overnight oats recipes on my website, I've been asked many times about the best mason jar for overnight oats. Each time I answer, I think "I should just write a post and explain which ones work best!" Below, you'll find various container options and tips for storing overnight oats, so they stay fresh.

Making overnight oats the night before is a smart way to plan ahead and have a delicious, hearty breakfast ready for you to grab the next morning. Whether you like to prep yours in a glass jar or plastic container, there’s something for you.
Best Jars for Overnight Oats
The best jar and container for overnight oats should have:
- Wide opening
- Leak-proof lid
- Microwave-safe
- Freezer-friendly
The options I’ve provided below, check off all the boxes and make your breakfast look cute will doing so. I filmed a quick video so you can see each of the jars in action!

Note: I used these taller 16oz mason jars in the photo at the top of this post. But if I had to choose a favorite, I'd go with the wide-mouth version as the best for single-serve mason jars. It is so much easier to stir in toppings when you have a wide-mouth jar.




What Size Jar for Overnight Oats
You want a jar that gives plenty of room for a hearty portion of oats and mix-in’s, so anything from 8 to 16 ounces is ideal for a single-serve jar.
Keep in mind, jars with a wide openings also make it easier to prep and eat the oats.
How Long do Overnight Oats Last
Most overnight oats recipes will up to 5 days in a jar in the refrigerator, and for this reason, as well as their delicious, creamy texture, they are a breakfast phenomenon I like to prep ahead at the beginning of the week.
The one exception would be an overnight oats recipe with banana, like my Banana Overnight Oats. While these taste like a dessert for breakfast, the bananas get a little too mushy after 3 days, which isn’t often a problem since they usually disappear by day 2.
Ratio for Overnight Oats in a Mason Jar
I’ve got the ratio of oats to liquid for overnight oats down to a science. Below is my base recipe that’s fail-proof, and you can make all your own by adding different fruit, seeds, and nuts. Here’s what you’ll need for each serving:
- ½ cup old-fashioned oats
- ½ teaspoon ground flaxseed
- ¾ cup milk
- ¼ teaspoon vanilla extract
- ½ cup chopped fruit
Mason Jar Overnight Oats

Watch how it’s made:
Ingredients
- 2 cups old fashioned oats
- 2 teaspoons ground flaxseed
- 3 cups milk, your choice
- 1 teaspoon vanilla extract
- 2 cups chopped fruit of your choice
Instructions
- Place four jars on a flat surface. Fill each jar with ½ cup oats, ½ teaspoon ground flax, ¾ cup milk, and ½ teaspoon vanilla. Stir to combine. Top with strawberries and refrigerate.
- In the morning, stir to combine. Warm up if desired or enjoy cold.







catherine says
I’ve become obsessed with overnight oats lately and I was looking for the best jars to use. thanks for all these ideas, ordering now!