Knit Ruffle Romper Pattern: Easy Baby Onesie, Newborn to 12 Months

The Delicate Knit Ruffle Romper is a sheer, lightweight knit baby onesie with optional ruffles on the back. It is knit with soft lace weight yarn on straight needles, closes with two buttons, and comes in four sizes from 0-3 months to 12 months. It has been one of my most requested outfits for newborn photography since I first released it, and it makes a beautiful heirloom gift too.

How Do You Knit a Baby Romper?

To knit a baby romper like this one, you knit the body flat on US 6 (4.0mm) straight needles with a soft lace weight yarn, add the ruffles with a third needle if you want them, then finish it with two buttons. The Delicate Knit Ruffle Romper pattern walks you through every size step by step, and it is rated easy.

Newborn baby sleeping in a purple knit ruffle romper and tiara, the Delicate Knit Ruffle Romper by Briana K Designs

From Newborn Only to Four Sizes

I first released this pattern in 2015 in newborn size only. It became such a favorite with photographers that I updated it with more sizes, so it now comes in 0-3 months, 3-6 months, 6-9 months and 12 months. If you already bought the pattern, the update is waiting for you in your Ravelry library.

Newborn wearing the Delicate Knit Ruffle Romper, a knit baby onesie pattern

Delicate Knit Onesie by Briana K Designs

The 12 month size was photographed by Stacia Ford Photography for this sweet Florida themed first birthday shoot.

Baby girl in a cream lace knit romper at a first birthday photo shoot — Image by Stacia Ford Photography

Knit Ruffle Romper Pattern Details

Skill level: Easy
Sizes: 0-3 months (3-6 months, 6-9 months, 12 months)
Finished width: 7.5 (8.5, 9.5, 10) inches
Height, neck to crotch: 8.7 (10, 11.5, 12.5) inches
Gauge: 19 sts and 28 rows = 4 inches in stockinette
Needles: US 6 (4.0mm) straight needles, plus a third needle (straight or circular) for the ruffles
Yarn weight: Lace (0)
Notions: stitch marker, row counter, sewing needle, scissors and 2 buttons
Terms: US knitting terms
Format: PDF pattern download

Best Yarn for a Knit Baby Romper

A fluffy lace weight yarn gives this romper its soft, see-through look in photos. I knit the samples in:

Aloft Super Kid Mohair from Crochet.com (shown in Fairy Tale)
Berroco Andean Mist (shown in Cerro Bayo)

Any lace weight (0) yarn that matches the gauge will work. Mohair and alpaca blends give the most halo for photos.

Briana holding up a burgundy Delicate Knit Ruffle Romper

Get the Delicate Knit Ruffle Romper Pattern

The full pattern is a PDF download with every size written out. You can get it in my Etsy shop or on Ravelry.

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This pattern is available in my shops:

Etsy Ravelry

Knit Baby Romper FAQ

What size needles do I need for this romper?

You need US 6 (4.0mm) straight needles, plus a third needle, straight or circular, for the optional ruffles.

Can I knit the romper without ruffles?

Yes. The ruffles are optional, so you can knit a simple, sheer onesie instead.

What sizes does the pattern come in?

It comes in 0-3 months, 3-6 months, 6-9 months and 12 months.

Is this knit romper good for newborn photos?

Yes! The sheer lace weight fabric and ruffles photograph beautifully, which is why photographers have requested it for years. It also makes a sweet keepsake or baby shower gift.