(4.82) Read Reviews

The Classic Crew Neck Undershirt


Our crew neck is perfect if you like to wear with your shirts fully buttoned up. Stay tucked and avoid embarrassing sweat stains with an incredibly soft, breathable feel.

Size & Fit Guide
3 shirt
Save 15%
5 shirt
workweek pack
Save 25%
10 shirt
stockpile pack
Save 30%
Free shipping on orders over $75. Free returns.


We back all of our undershirts with a 100-day guarantee. We’re so confident in them that in the unlikely event that the collar ‘bacon necks’ or a seam breaks, don’t sweat it! We’ll gladly replace it with a new one.


Tailored Fit &
Stays Tucked
Incredibly Soft
Won’t Pill
Fights Odor
All Day

The Most Comfortable Undershirt You’ll Ever Wear

The moment you put on an UnderFit undershirt, you’ll notice a huge difference compared to other undershirts you’re used to wearing. To design the best men’s undershirts, we analyzed everything we hated about traditional, poorly-made basics. That’s why we set out to make an undershirt that:

  • Works for the office, a night out, or around the house.
  • Features the highest-quality, comfortable fabrics.
  • Stays tucked in all day long (with no “undershirt gut”).
  • Offers anti-odor and advanced moisture absorption.
Slim fit crew neck undershirt moves with you
Crew neck undershirt with gray quarter-zip sweater

A Perfect Fit That Keeps You Cool, Crisp, & Confident

You don’t need a six-pack to rock an UnderFit undershirt. They say clothes make the man. At UnderFit, we know confidence starts underneath.

  • Look slimmer and feel more confident.
  • Stays tucked all day, no matter how you move.
  • Moisture wicking & odor resistant fabric keeps you feeling fresh.
  • Tailored fit hugs your biceps and waistline to eliminate lines and “t-shirt bulk” around your middle.

Ridiculously Soft & Sustainable

You’ll never want to take this undershirt off! Our undershirts are made from TENCEL™ fabric, a highly-sustainable textile sourced from wood chips. The trees are sustainably farmed and our manufacturing process is “closed-loop,” meaning there is little to no waste.

  • All-day breathability. Soft, light, and flexible.
  • Excellent durability. No pilling after extended wear.
  • Wicks 50% more moisture than cotton.
  • 1/20th the environmental impact of cotton.
Crew neck undershirt with button down dress shirt

It’s Easy to See Why People Get Obsessed

Hear it straight from the professionals

Gotta tell you, it’s a very nice product. Good fit, good feel, good price. Comparatively, the UnderFit fits and feels very close (or as nice as) to the more expensive micromodal/lycra undershirts.

The Undershirt Guy

No rising, No billowing. We managed to get through a whole day without a single untuck from under our made-to-measure shirts.

The Gents Staff
Gents Among Men

The problem with most undershirts is that they’re just T-shirts. UnderFit’s shirts are made from lightweight yet durable fabrics with a touch of stretch and are designed to be worn under your shirts.

Valet Staff
Valet Mag

The Fit

A Perfect Fit. Guaranteed

All of our undershirts are backed by a 100-day guarantee. Don’t love it? Contact us and we’ll make it right.

  • 20k+

    Happy Customers

  • 140k+

    Undershirts Sold

  • 100%

    Free Returns & Exchanges

Frequently Asked Questions

If we haven’t answered your questions here, hit our chat or email us at [email protected]

TENCEL™ Fabric Feel

Why do we use our TENCEL™ blend and not cotton?

Should I get a crew neck or a v-neck undershirt?

Why do UnderFit undershirts cost more than cotton basics?

How do UnderFit undershirts stay tucked all day long?

What is the right fabric (moisture absorbing vs wicking) to wear?

What’s wrong with viscose, bamboo, organic cotton or other fabrics?

Where are the shirts made?

Finding The Right Fit

How does it fit?

Will it tighten to pull my belly in?

Will it feel tight?

Customer Service Questions

What if I try UnderFit and don’t like it?

What is your returns policy?

Do you ship worldwide?