What Is Sizing Like at Sister Jane?

By Ella Blake — Fashion Stylist | Tellar Fashion Hub — Always honest, unbiased & unsponsored

Sister Jane sizes on the smaller side — I'd recommend sizing up one size from your usual UK size, particularly in dresses and anything with a defined waist. It's a London-based label I absolutely adore, but I've been caught out by it more than once. That beautiful feather-trimmed midi I ordered in my usual 12? Technically on, technically zipped — but definitely not comfortable. Learn from my mistakes. Go up, and enjoy the magic.

Who Is Sister Jane?

If you're not already familiar, Sister Jane is a London-founded womenswear brand built on romantic, vintage-inspired silhouettes — think puff sleeves, broderie anglaise, floaty midis, and the kind of whimsical florals that make you feel like you've wandered into a really well-dressed countryside wedding. The brand has a devoted following and is regularly stocked at ASOS and various boutiques globally, as well as direct through their own site. It's mid-market in price, very fashion-forward in look, and has become something of a cult favourite among the cottagecore and romantic-dressing crowd.

The aesthetic is genuinely beautiful. But — and this is important — the brand is not built for everyone's body. The fits are designed with a very specific silhouette in mind: nipped waist, narrower shoulders, and a romantic feminine cut that prioritises visual drama over ease of movement. If that's your shape, you'll be in heaven. If not, read on, because there are ways to make it work.

Sister Jane Size Guide — UK, US & EU Conversions

Sister Jane uses a blend of XS–XL sizing and numerical sizing depending on the piece and season. Here's how their sizing maps to standard UK, US, and EU equivalents, along with body measurements:

Sister Jane LabelUK SizeUS SizeEU SizeBust (cm)Waist (cm)Hips (cm)XS6–82–434–3680–8461–6587–91S8–104–636–3884–8865–6991–95M10–126–838–4088–9269–7395–99L12–148–1040–4292–9673–7799–103XL14–1610–1242–4496–10077–81103–107

Because sizing spans two UK sizes per label, and because of the brand's narrower cut, always size up if you are between sizes. For pieces with defined waist seams, structured bodices, or fitted sleeves — which covers a large proportion of their range — going up is almost always the right call.

Fit by Garment — What You Need to Know Before You Buy

Sister Jane is not a one-size-fits-all brand in terms of cut. Here's my honest breakdown of how the sizing plays out across different garment types:

Midi and Maxi Dresses: This is Sister Jane's signature category and where the fit is most critical to get right. Bodices are typically structured and fitted, with the waist nipped in. If you have a fuller bust or broader shoulders, size up without question — the bodice will not forgive you otherwise. The skirt portion is almost always full and generous, so it's the top half that drives the sizing decision.
Mini Dresses: Often slightly more forgiving in cut, but the same general rule applies — go up if in doubt. Some mini styles have elasticated waists which give a little more flexibility, so always check the product description.
Blouses & Tops: These can run particularly small across the shoulders and chest. I find their tops tend to suit narrower frames best. If you have broader shoulders or a fuller bust, size up by at least one, and check for any stretch content in the fabric.
Skirts: Generally the most straightforward category. Full skirts with elasticated waistbands are very size-flexible. Pencil or A-line styles will follow standard sizing more closely, so measure your waist and hips against the size guide before ordering.
Coats & Jackets: Sister Jane's outerwear is more generous in cut, designed to layer over their voluminous dresses. True to size or occasionally roomy — their coats are one area where you don't necessarily need to size up.
Knitwear: Relaxed and usually true to size. One of the more forgiving categories in their range if you want a cosy, easy fit.

A Note on Fabric and Structure

Sister Jane works heavily in woven fabrics — structured cottons, satin-finish materials, organza, and lace. There is very little stretch in most of their core pieces. This is part of what makes them look so beautiful and editorial, but it also means the fit is less forgiving than jersey or stretch-woven brands. Always check the fabric composition before buying: if there's no elastane in the mix, your measurements need to sit comfortably within the size guide, not right at the boundary of it.

Is Sister Jane Worth It?

Honestly, yes — if you love the aesthetic and you get the sizing right, the pieces are genuinely special. The quality at the price point is solid, the designs are consistently original, and nothing else quite looks like it on the high street. But it's not a brand I'd buy from without checking the size guide first. Once you know your Sister Jane size, you can shop with confidence. Until then, size up and read the reviews.

Best Alternatives If You Love the Sister Jane Look

If Sister Jane's romantic, vintage-inspired aesthetic appeals but the fit isn't working — or you simply want to explore similar territory at different price points — here are my top picks:

High Street Options:

Anthropologie — The closest high street match to Sister Jane's romantic sensibility. Beautiful prints, floaty silhouettes, and a similar devotion to feminine, occasion-worthy dressing. Sizing is more consistent and inclusive, and the quality is excellent for the price.
Monsoon — A long-standing favourite for feminine occasion dressing. Think embroidered midis, floral maxi dresses, and rich print work. Sizing is generous and accommodating, making it ideal if Sister Jane cuts too small for you.
Topshop (via ASOS) — The revived Topshop range carries some genuinely lovely romantic and vintage-influenced pieces, particularly in dresses. A useful alternative for the younger end of the Sister Jane customer base.
Whistles — For a more refined, grown-up take on feminine dressing. Whistles' floral and occasion pieces are beautifully cut and more forgiving in the shoulder and bust. A reliable step up in quality from pure high street.
Oliver Bonas — Criminally underrated for occasion-worthy dresses and romantic florals. Great value, inclusive sizing, and genuinely on-trend without being derivative. A brilliant budget-friendly alternative to Sister Jane.
Great Plains — Wonderful for romantic prints, linen dresses, and softly structured pieces. Slightly more understated than Sister Jane but similar in spirit, and the sizing is consistent and true.
Coast — Perfect if you're after Sister Jane-esque occasion wear with a broader size range and a slightly more classic edge. Brilliant for weddings and events where you want something beautiful but reliable in fit.

Premium Step-Up:

LK Bennett — For elevated feminine occasion dressing with better quality construction. Their printed silk-style dresses and vintage-leaning silhouettes share DNA with Sister Jane but are cut with a more experienced customer in mind. Sizing is true and consistent.
Claudie Pierlot — A French brand that occupies similar romantic territory with considerably more sophistication. Beautiful broderie, floral prints, and feminine cuts — but with a Parisian restraint that elevates everything. Runs small, so size up here too.

Independent Picks:

Rixo — The premium independent label that is probably the closest spiritual match to Sister Jane's vintage-romantic sensibility. Iconic vintage-inspired prints, tea dresses, and midi silhouettes. Quality is exceptional and the fit, while equally structured, is better cut for a range of body types. A genuine upgrade if you love Sister Jane's world.
Nazli Ceren — A small London-based independent label producing utterly romantic, handmade-feel occasion pieces. Puff sleeves, dramatic florals, broderie anglaise — everything Sister Jane fans obsess over, but in limited-run, more considered pieces. Well worth knowing about if you want something truly individual.

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