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Flash Sale: Extra 15% off⁹ with code AFTERHOURS

King Size Mattress in a Box

280

results

King

Best Seller

Perfect Sleeper® Charlotte 2.0 Medium Euro Top Mattress

Serta Perfect Sleeper® Charlotte 2.0 Medium Euro Top Mattress

King

Medium Comfort, best for

All Sleep Positions
Pain
Toss and Turn

6 Sizes

72 hour sale ends Monday!

Delivery in6+ weeks

Best Seller

Midnight Dream 14.25" Ultra Plush Pillow Top Mattress

Beauty Sleep® Midnight Dream 14.25" Ultra Plush Pillow Top Mattress

King

Ultra Plush Comfort, best for

Side Sleepers
Toss and Turn
Bed Partner

6 Sizes

72 hour sale ends Monday!

Delivery in6+ weeks

Best Seller

By Sealy® Slumber Firm Mattress

Sleepy's By Sealy® Slumber Firm Mattress

King

Firm Comfort, best for

Back and Stomach Sleepers
Bed Partner
Toss and Turn

6 Sizes

72 hour sale ends Monday!

Delivery in6+ weeks

Best Seller

By Sealy® Medium Euro Top Mattress

Sleepy's By Sealy® Medium Euro Top Mattress

King

Medium Comfort, best for

All Sleep Positions
Pain
Temperature

7 Sizes

FREE ADJUSTABLE BASE³ up to $499 value with code ELEVATE (must add base to cart)

Delivery in6+ weeks

Best Seller

PressureSmart™ 2.0 Firm 11" Mattress

Beautyrest PressureSmart™ 2.0 Firm 11" Mattress

King

Firm Comfort, best for

Back and Stomach Sleepers
Pain
Temperature

8 Sizes

72 hour sale ends Monday + FREE adjustable base with code ELEVATE (must add base to cart)

Delivery in6+ weeks

Having trouble deciding?

Best Seller

BR800 13.5" Plush Pillow Top Mattress

Beautyrest BR800 13.5" Plush Pillow Top Mattress

King

Plush Comfort, best for

Side Sleepers
Toss and Turn
Pain

7 Sizes

72 hour sale ends Monday + FREE adjustable base with code ELEVATE (must add base to cart)

Delivery in6+ weeks

Best Seller

Silver® BRS900-C 13.75" Extra Firm Mattress

Beautyrest Silver® BRS900-C 13.75" Extra Firm Mattress

King

Extra Firm Comfort, best for

Back and Stomach Sleepers
Bed Partner
Pain

6 Sizes

72 hour sale ends Monday + FREE adjustable base with code ELEVATE (must add base to cart)

Delivery in6+ weeks

Best Seller

Midnight Dream 14.25" Medium Pillow Top Mattress

Beauty Sleep® Midnight Dream 14.25" Medium Pillow Top Mattress

King

Medium Comfort, best for

All Sleep Positions
Toss and Turn
Bed Partner

6 Sizes

72 hour sale ends Monday!

Delivery in6+ weeks

Best Seller

Basic Innerspring Firm Mattress

Sleepy's Basic Innerspring Firm Mattress

King

Firm Comfort, best for

Back and Stomach Sleepers

5 Sizes

Delivery in6+ weeks

Best Seller

By Sealy Memory Foam Plush Mattress

Sleepy's By Sealy Memory Foam Plush Mattress

King

Plush Comfort, best for

Side Sleepers
Pain
Bed Partner

6 Sizes

72 hour sale ends Monday!

Delivery in6+ weeks

Only at Mattress Firm

Perfect Sleeper® Sleep Excellence™ Plush Mattress

Serta Perfect Sleeper® Sleep Excellence™ Plush Mattress

King

Plush Comfort, best for

Side Sleepers
Pain
Toss and Turn

6 Sizes

FREE ADJUSTABLE BASE³ up to $499 value with code ELEVATE (must add base to cart)

Delivery in6+ weeks

BR800 12" Plush Euro Top Mattress

Beautyrest BR800 12" Plush Euro Top Mattress

King

Plush Comfort, best for

Side Sleepers
Toss and Turn
Pain

7 Sizes

FREE ADJUSTABLE BASE³ up to $499 value with code ELEVATE (must add base to cart)

Delivery in6+ weeks

Best Seller

TEMPUR-ProAdapt® 12" Medium Hybrid Mattress

Tempur-Pedic TEMPUR-ProAdapt® 12" Medium Hybrid Mattress

King

Medium Comfort, best for

All Sleep Positions
Pain
Bed Partner

7 Sizes

Receive $300 Instant Gift⁴ with purchase.

Delivery in6+ weeks

Best Seller

Black® Series Three 16.75" Plush Pillow Top Mattress

Beautyrest Black® Series Three 16.75" Plush Pillow Top Mattress

King

Plush Comfort, best for

Side Sleepers
Pain
Bed Partner

6 Sizes

FREE ADJUSTABLE BASE³ up to $499 value with code ELEVATE (must add base to cart)

Delivery in6+ weeks

14 of 280 results

King Size Mattress in a Box

Mattress in a box offers convenience and high-quality sleep. Temperature-regulating components and materials draw heat away from the body to create a cool and comfortable sleep surface. Check out the mattress in a box selection available, including many bed options on sale.

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