What to Wear Under a Knit Sweater: The Complete Layering Guide

Layering under a knit sweater seems straightforward — until you end up with bunched-up sleeves, visible seam lines or a base layer that adds so much bulk you look two sizes larger. Getting the underlayer right is a quiet art that makes a big difference in how your outfit looks and feels.

Whether you are layering for warmth, modesty or style, here is what to wear under a knit sweater for every scenario.

The Everyday Essential: A Fitted T-Shirt or Camisole

For most situations, a simple fitted crew-neck or V-neck t-shirt in a lightweight cotton or modal fabric is all you need. It creates a smooth base layer that prevents the knit from sitting directly on skin — which can feel itchy with some wool blends — and absorbs perspiration to keep your sweater fresher between washes.

A camisole or thin-strap tank top works even better under close-fitting knits. The thinner straps eliminate any bulk at the shoulders and sleeves, giving the sweater a cleaner silhouette.

Best colours: Match the base layer to your skin tone or to the sweater colour. White under light knits, black or charcoal under dark ones. Avoid bright colours under lighter or open-knit sweaters unless you want the contrast to show through.

For Visible Layering: A Collared Shirt

The classic shirt-under-sweater combination is a style staple for good reason. A crisp white or light blue button-down shirt layered under a crew-neck or V-neck sweater creates a polished, preppy look that works for the office, smart-casual events or weekend outings.

Tips for making this look sharp:

• Choose a slim-fit shirt to minimise bunching under the sweater.
• Pop the collar up slightly above the sweater neckline for a clean frame around the face.
• Let the shirt cuffs peek out about one to two centimetres below the sweater sleeves for a tailored detail.
• Leave the shirt hem untucked for a casual vibe, or tuck it in for a sleeker look — especially with higher-waisted trousers.

For Warmth: A Thermal or Merino Base Layer

When the temperature drops seriously, a thin thermal base layer is the smartest way to add warmth without bulk. Merino wool base layers are ideal — they regulate temperature, wick moisture and sit flat under knitwear.

Look for base layers that are:

• Lightweight (150 to 200 gsm) — enough warmth without thickness.
• Close-fitting — loose base layers create unflattering lumps.
• Seamless or flat-seamed — visible seam ridges through a knit sweater look messy.

Synthetic thermals (polyester fleece, for example) work too but tend to trap odour more than natural fibres. For an underlayer you may wear all day, merino is worth the investment.

For Open-Knit or Sheer Sweaters: A Lace Bralette or Bandeau

Open-stitch and semi-sheer knits are designed to show a hint of what is underneath. This is where a pretty lace bralette, a structured bandeau top or a sleek bodysuit becomes part of the outfit rather than just a practical layer.

Choose a base that you are happy to have visible: a black lace bralette under a cream open-knit sweater, for example, or a tonal satin camisole for a more subtle effect. This look works beautifully for evening and weekend styling.

For V-Neck and Off-Shoulder Knits: A Seamless Bra or Strapless Top

Low necklines and off-shoulder styles demand a base layer that stays invisible. A seamless, skin-toned bra or adhesive bra keeps things smooth under V-neck and wide-neck knit tops. For off-shoulder sweaters, a strapless bandeau or tube top works well — choose one with a silicone grip so it stays in place.

For Knit Dresses: Shapewear or a Slip

Under a body-conscious knit dress, a lightweight slip or smoothing shapewear can make a noticeable difference. It creates a cleaner line, prevents static cling and adds a layer of modesty if the knit is finer than expected.

A classic slip dress in a matching colour is the most comfortable option. If you prefer more structure, modern seamless shapewear shorts or a body-smoothing camisole will achieve a polished look without discomfort.

What Not to Wear Under a Knit Sweater

• Thick hoodies or sweatshirts — too bulky, they distort the sweater's shape.
• Lace-trimmed or embellished tops (unless intentionally visible) — decorative details create visible texture bumps under knitwear.
• Padded or heavily structured bras under thin knits — the outline shows through. Opt for smooth, moulded cups or bralettes.
• Tops with large logos or graphics — the print can show through lighter knits as a shadow.

The Golden Rule of Layering Under Knitwear

The base layer should always be thinner and smoother than the knit over it. When in doubt, go lighter. A barely-there camisole or seamless tee will always look and feel better under a sweater than something with bulk, texture or structure competing for attention.

The sweater is the star — everything underneath should support it invisibly. Explore our sweater collection and knit tops to find pieces that layer beautifully in any season.