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Period Underwear

Period Underwear

Period Underwear changes everything

Get period underwear from the leaders in leakproof.

Shop by Style

French Cut High Rise Bikini Boyshort Boxers & Shorts Thong Cheeky Leakproof Thigh Saver Shorts

The best thing to happen to periods ever

Imagine the confidence you’ll feel in underwear that absorbs the same as about 8 regular tampons. And they feel and wash just like regular undies.

★★★★★

“They fit perfectly AND handle my heavy days beautifully.”
Sonya S.

FIND THE BEST PAIR FOR YOU

FIND THE BEST PAIR FOR YOU

Covered for everything

FIND YOUR PERFECT PAIR

✓ For light days or backup protection

✓ Full replacement of disposables on heavy days

✓ Protection day or night

✓ Save 15% on any 3+ pairs or 25% on 6+ pairs

Catalyst Front Zip Sports Bra

Super supportive with a front closure for easy on & off. Maximum support.

Momenta Racerback Sports Bra

A classic racerback cut with built-in padding and mesh detailing. Medium support.

Underwear Style

French Cut

French Cut

High Rise

High Rise

Bikini

Bikini

Boyshort

Boyshort

Shorts + Boxer Briefs

Shorts + Boxer Briefs

Leakproof Thigh Savers

Thigh Savers

Thong

Thong

Cheeky

Cheeky

“I bought 11 pairs and I’m never turning back.”

“I bought 11 pairs and I’m never turning back.”

“I bought 11 pairs and I’m never turning back.”

Sandra P.

“I haven’t felt this secure, comfortable and protected ever.”

“I haven’t felt this secure, comfortable and protected ever.”

“I haven’t felt this secure, comfortable and protected ever.”

Sheny T.

“I can’t believe I’ve gone so long without these!”

“I can’t believe I’ve gone so long without these!”

“I can’t believe I’ve gone so long without these!”

Liz

“I bought 11 pairs and I’m never turning back.”

“I bought 11 pairs and I’m never turning back.”

“I bought 11 pairs and I’m never turning back.”

Sandra P.

“I haven’t felt this secure, comfortable and protected ever.”

“I haven’t felt this secure, comfortable and protected ever.”

“I haven’t felt this secure, comfortable and protected ever.”

Sheny T.

Ways to save

Save up to 20%

Bundle & Save up to 25%

Stock up and save when you buy more pairs.
For a limited time, including Teen Underwear!

Save on Period Kits

Save on Period Kits

Skip the guesswork with curated Period Underwear Kits and save 10–15%

Earn points with Knix Rewards

Earn points with Knix Rewards

Spend $1, earn 1 point every time you shop. Redeem $10 every 100 points.

Knix Founder, Joanna Griffiths explains Period Underwear

More ways to feel unapologetically free

More ways to feel unapologetically free

More ways to feel unapologetically free

Find an amazing wireless bra to match your Undies. Plus explore our other products, all designed to make you feel so comfortable in your own skin.

BRAS Period Underwear EVERYDAY UNDERWEAR SLEEPWEAR ACTIVEWEAR APPAREL Maternity

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Best Sellers

Amber has 38" hips and wears a Knix size M color:midnight

Leakproof French Cut

Ottavia has 44" hips and wears a Knix size L color:savanna

Leakproof French Cut

Ottavia has 44" hips and wears a Knix size L color:orchid

Leakproof Bikini

Becca has 47" hips and wears a Knix size XL color:berry

Leakproof High Rise

Maya has 47" hips and wears a size XL color:dark cherry

Super Leakproof Dream Short

Amber has 38" hips and wears a Knix size M color:orchid

Leakproof Boyshort

Emma has 53" hips and wears a Knix size XXXL color:rose water

Super Leakproof Bikini

Amber has 38" hips and wears a Knix size M color:berry

Super Leakproof Thong

Emma has 53" hips and wears a Knix size XXXL color:olive

Cotton Super Leakproof Boxer Brief

Amber has 38" hips and wears a Knix size M color:midnight

Cotton Modal Super Leakproof High Rise

Becca has 47" hips and wears a Knix size XL color:berry

(kit item) Good Routine Period Kit Leakproof High Rise Berry | High Rise

Save 14%

Thigh Savers

SHOP ALL

Chloe has 47" hips and wears a size XL color:sable

Shortie Thigh Saver 4"

Marlene has 50" hips and wears a Knix size XXL color:sola

Thigh Saver 6"

Front View color:warm sand

Leakproof Thigh Saver 6”

color:leopard print

Papaya Thigh Saver - Leopard

color:papaya pink

Papaya Thigh Saver - Lace

color:black

Papaya Thigh Saver - Lace

color:toasted

Papaya Thigh Saver - Lace

Super Leakproof Underwear

SHOP ALL

Maya has 41" hips and wears a Knix size L color:zebra

Super Leakproof High Rise

Ottavia has 44" hips and wears a Knix size L color:midnight

Super Leakproof Dream Short

Becca has 47" hips and wears a Knix size XL color:orchid

Super Leakproof Bikini

Ottavia has 44" hips and wears a Knix size L color:berry

Super Leakproof Boyshort

Amber has 38" hips and wears a Knix size M color:orchid

Super Leakproof Thong

Candice has 50.5" hips and wears a Knix size XXL color:zebra

Super Leakproof Cheeky

Becca has 47" hips and wears a Knix size XL color:olive

Cotton Modal Super Leakproof Bikini

Ottavia has 44" hips and wears a Knix size L color:orchid

Cotton Modal Super Leakproof High Rise

Amber has 38" hips and wears a Knix size M color:orchid

Cotton Super Leakproof Boxer Brief

Becca has 47" hips and wears a Knix size XL color:midnight

Full Coverage Cotton Modal Super Leakproof Bikini

Ottavia has 44" hips and wears a Knix size L color:midnight

Full Coverage Cotton Modal Super Leakproof High Rise

style:highrise color:cavassa

Heavy Flow Period Kit

Save 14%

Leakproof Underwear

SHOP ALL

Siobhan has 36" hips and wears a size S color:zebra

Leakproof French Cut

Becca has 47" hips and wears a Knix size XL color:orchid

Leakproof High Rise

Ottavia has 44" hips and wears a Knix size L color:midnight

Leakproof Bikini

Amber has 38" hips and wears a Knix size M color:berry

Leakproof Boyshort

Amber has 38" hips and wears a Knix size M color:rose water

Leakproof Cheeky

Candice has 50.5" hips and wears a Knix size XXL color:zebra

Leakproof Thong

Amber has 38" hips and wears a Knix size M color:berry

Leakproof High Rise Thong

Amber has 38" hips and wears a Knix size M color:orchid

Super Leakproof Thong

Becca has 47" hips and wears a Knix size XL color:orchid

Shadow Mesh Leakproof Bikini

Claire has 35" hips, 24" waist and wears a Knix size S color:rose water

Shadow Mesh Leakproof High Rise

Sofia has 38" hips, 26.5" waist and wears a Knix size M color:Periwinkle

Shadow Mesh Leakproof Boyshort

Amber has 38" hips and wears a Knix size M color:orchid

Shadow Mesh Leakproof Thong