5 Little Monkeys Mattress Review (2026): A Mattress Built Just for Growing Kids

5 Little Monkeys at a Glance

5 Little Monkeys is a kids-only mattress brand. Its main product, the Kids Mattress Sleep System, bundles an 8-inch memory foam mattress with a kids' pillow and a waterproof protector. It also sells a 9-inch Advanced Hybrid with coils, plus bases, sheets and bedding.

The brand comes from a long-running family bedding business. According to 5 Little Monkeys, founder Jason Harrow ran Hollywood Bed, the company his grandfather Irving Harrow founded in 1945, and created the Sleep System in 2016 when his daughters were ready to move from cribs to big-kid beds.

The 5 Little Monkeys Kids Mattress Sleep System

The Sleep System is the brand's best-known product. It's sold as a bundle so parents get everything for a big-kid bed in one box: the mattress, a pillow sized and filled for smaller bodies, and a waterproof protector.

What's Inside the 5 Little Monkeys Mattress

5 Little Monkeys describes a three-layer, all-foam design. All three foam layers are polyurethane and CertiPUR-US certified.

The company says the responsive support layer suits children's lighter bodies, and the open-cell comfort foam and gel are meant to manage heat. The cover is the part most parents will appreciate: it zips off and goes in the washing machine.

Sizes and Weights

At 31 pounds for a twin, it's easy for one adult to move and rotate.

Firmness and Feel

5 Little Monkeys calls the feel "Cushion Firm," around a 7 on a 1-to-10 scale. That's on the firmer side of medium, with a cushioned top layer. For most children, a medium-firm surface balances comfort and support, because kids are lighter than adults and don't sink as far into the foam.

Firmness is personal. If your child finds it too firm or soft, the 100-night trial gives you time to decide.

The Bundle: Pillow and Protector

The protector matters for two reasons: kids have accidents and spills, and the warranty requires you to use the company's protector. It's warrantied for 1 year or 34 washes, after which the waterproof backing may become less effective. See our guide to the best waterproof mattress for bedwetting.

The 9-Inch Advanced Hybrid

The Advanced Hybrid adds individually wrapped coils under the foam, for more bounce and airflow. It's 9 inches tall, still low enough for many bunk beds, and comes in twin (41 lb), full (58 lb) and queen (69 lb). It carries the same 100-night trial and 15-year warranty, but it isn't sold as part of the pillow-and-protector bundle.

Safety and Certifications

5 Little Monkeys doesn't describe its fire barrier material on its product pages. If that matters to you, ask the company before you buy. See our guide to mattresses without fiberglass.

Bunk Beds, Trundles and Platform Beds

5 Little Monkeys says the mattress height was designed for bunk beds and that it fits trundle beds. It also works on platform beds, daybeds and most solid or slatted foundations.

For bunk beds, the US safety standard calls for guardrails to extend at least 5 inches above the top of the mattress. Check your bunk bed's label or manual for its maximum mattress thickness. An 8-inch mattress fits many bunk beds, but not all.

Delivery, Trial and Warranty

Pros and Cons

Who Should Buy a 5 Little Monkeys Mattress?

Good Fit

• Parents moving a child from a crib or toddler bed to a twin.
• Bunk beds and trundles that need a low-profile mattress.
• Families who want a washable cover and a protector in the box.
• Kids who sleep hot, thanks to open-cell foam and gel.

Consider Something Else If

• Your child prefers a bouncy, springy bed (look at the hybrid).
• You want all-natural or organic latex. See our best organic mattress guide.
• Your child is under 3. See our guide to the best organic crib mattress.

5 Little Monkeys vs. Other Kids' Mattresses

See our guide to the best mattress for kids for more options.

Is an 8-Inch Mattress Thick Enough for a Child?

Adult mattresses are often 10 to 14 inches thick because adults are heavier and need deeper comfort layers. Kids weigh much less, so they don't press as far into the foam. An 8-inch, three-layer mattress gives a child a cushioned top and a supportive base without the height that makes bunks and trundles unsafe or impractical.

If your teen is heavier or prefers a deeper feel, the 9-inch Advanced Hybrid adds coils for more support and bounce.

Temperature and Sleeping Hot

Kids often sleep warm, and memory foam can hold heat. 5 Little Monkeys addresses this in three ways, according to the company:

• Open-cell memory foam in the comfort layer, which lets air move through the foam.
• Dual Phase Change Gel, which the company says regulates temperature.
• A breathable cover with organic cotton.

If your child sleeps very hot, the hybrid's coil layer adds more airflow. Light, breathable sheets (cotton percale) and a cooler room help too.

Moving From a Crib to a Big-Kid Bed

5 Little Monkeys was created for this transition. A few tips for making it go smoothly:

Most children make the move between about 18 months and 3 years. 5 Little Monkeys says its mattresses are for ages 3 and up.

Caring for a 5 Little Monkeys Mattress

The protector is warrantied for 1 year or 34 washes. With frequent washing, plan to replace it periodically.

How to Buy and What to Expect on Delivery

The mattress ships compressed in a 48" x 17" x 17" box. Open it in the room where it will go, cut the plastic carefully, and give the foam time to expand before your child sleeps on it. A light new-foam smell is normal and usually fades with airing.

Sign up for emails or check the site during sales events, since 5 Little Monkeys often runs promotions on the bundle, bedding and bases. See our guide to when mattresses go on sale.

Frequently Asked Questions

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