We Tested 8 Popular Knee Pillows to Find the 4 Best Styles for Side Sleepers

Sleep Number's Knee Pillow comes with high praise from thousands of online reviewers, but it earned mixed feedback from our testers. Some found it too thin, while others disliked the shape. Still, it washed well, and testers liked the soft, fleece cover and the minimal footprint. If you find a normal down or fiberfill pillow too thick, you might like this, but so far, in our tests, the results are inconclusive.

Tempur-Pedic's All Purpose Pillow uses their popular pressure-relieving foam. Its peanut shape is versatile, so you can use it as a neck pillow or lumbar pillow, and its compact size makes it especially great for travel. Our testers liked this multi-purpose aspect, but several found it too small for using between their knees.

Noble's Lower Body Pillow is great if you're looking for a body pillow for putting between your legs, but, like most body pillows, it's large. It's on the pricey side, but it comes with extra fill to adjust the shape and firmness and offers supportive latex and wool options. But it's not super intuitive: It comes with a lot of instructional pamphlets that are worth thoroughly reading through.

There are a few other popular pillows we're hoping to test next, such as Pillow Cube's Knee Cube, the Contour Legacy Leg & Knee Foam Pillow and Everlasting Comfort's Knee Pillow with Straps. All have either unique shapes or features compared to our current top-tested picks.

After testing more than 175 pillows in recent years, we've refined our pillow-testing process. Here are some of the key metrics we consider:

• Durability/washability: We first score each pillow on its care label instructions for how easy it is to clean. From there, we wash the pillows (or pillowcases) and closely observe any changes after both the initial wash and several washes.
• Ease of use: For styles with a removable pillowcase, we gauge how easy it is to put the pillowcase back on after laundering.
• Performance: Depending on the type of fill and pillow shape, we'll place weights on each pillow for a set amount of time before recording how long it takes for the material to fully recover (or bounce back). We also take note of how the material responds to this weight (e.g. whether it sinks in or holds its shape).
• Consumer testing: To ensure each pillow gets a fair test, we match consumer testers with a pillow based on their personal preferences and sleeping style. Users then try out the pillow over a series of weeks prior to rating it on overall comfort, support, temperature regulation and more. They then provide in-depth feedback on their experience.

✔️ Material/fill: Most knee pillows we found online are made of solid memory foam, though some instead use a fiberfill.

• Memory foam is known for its pressure relief, but most knee pillows will either feel notably firm and supportive or soft and cushiony. If you want firmer support, look for high-density foam.
• Polyester fiberfill often has a fluffier texture and offers more breathability than foam, which has a tendency to trap heat.

✔️ Size, shape and firmness level: Many orthopedic knee pillows you'll find have a similar look with an hourglass-like contoured shape and either a firm or cushioning feel. The most important aspect is how wide the gap between your knees or legs is when using it.

Make sure to check if your body feels aligned with the pillow: If your legs tilt inwards, look for a thicker, firmer option. If they extend outwards, you'll need a slimmer or softer style.

✔️ Care: Unlike bed pillows, there aren't standardized sizes or cases for knee pillows, so you'll need to rely on the case sold specifically for your model. Make sure the case (and the pillow itself, if washable) are easy to care for and fit into your laundry routine.

For side-sleeping patients with hip issues like arthritis or bursitis, Dr. Kirschner typically recommends sleeping with a pillow between the knees or legs to prevent excessive pressure in key areas.

So if you're struggling with knee or hip pain as a side sleeper, sleeping with any kind of pillow between your legs — whether an orthopedic knee pillow, a body pillow or a regular pillow — is worth trying. Still, Dr. Kirschner cautioned, "There is no one best approach. The most important thing is finding a pillow and position that is comfortable to you."

Based on our consumer tester feedback, I'd agree. Here's what I'd recommend: If you're unsure about what to do, start by sleeping with a spare pillow (if you have one) between your legs or knees before investing in a body pillow. If you like using that, great! If you wish it was a tad more supportive, I'd think about investing in a body pillow or knee pillow.

If you go the route of purchasing a knee pillow, allow for an adjustment period, similar to a new mattress. It can be an odd experience. If you move around in your sleep, you might even wake up to find the pillow on the floor for the first few days.

Yes and no, despite their similarities in shape, most orthopedic knee pillows can vary greatly depending on the firmness level and size, so it can be hit or miss.

For some of our testers, including a few with hip bursitis, a knee pillow proved notably helpful in promoting alignment. Several testers, however, preferred using a normal pillow (like the ones you typically sleep on) or a full-size body pillow as some knee pillows felt too firm for alignment or too short for personal comfort.

I'd recommend knee pillows to those who want firm support and don't care for coverage around the entire leg. If you like the coverage of a normal pillow but want a firmer feel, consider our pick from The Company Store or opt for a body pillow instead.

At the Good Housekeeping Institute Textiles Lab, we've reviewed our fair share of pillows (over 175!), relying on in-Lab testing, thorough feedback from at-home testers and the scientific expertise of our textiles analysts.

Grace Wu is textiles product review analyst at the Good Housekeeping Institute. Beyond knee pillows, she's also tested various ergonomic pillows, from pillows for neck pain to lumbar support pillows and seat cushions. Prior to joining GH, she earned a Masters of Engineering in materials science & engineering and a Bachelor of Science in fiber science from Cornell University.

For this story, she consulted notes from past interviews with Jonathan S. Kirschner, M.D., RMSK is a physiatrist at the Hospital for Special Surgery (HSS) in New York City.