Black Tie Optional Dresses: What to Wear and How to Choose

A black tie optional dress is a floor-length evening gown and a polished, formal cocktail dress, such as a dressy midi dress in satin, velvet and embellished fabrics, because the dress code tells guests that a tuxedo is welcome but not required, and women match that level of formality. The SIMKHAI picks below cover both lengths.

Key facts

• Black tie optional lets men choose a tuxedo and a dark suit; women dress as formally as for black tie.
• A floor-length gown and a formal midi in satin, velvet and embellishment are both correct.
• Fabric signals formality more than length: a velvet midi reads more formal than a jersey maxi.
• Wedding guests should avoid white and ivory unless the couple ask for it.

What black tie optional means

The phrase comes from menswear. At black tie, men wear a tuxedo. At black tie optional, they may wear a tuxedo and may wear a dark suit with a tie. For women the translation is simple: dress as formally as you would for black tie, with a little more room on length. A gown is always right. A sophisticated cocktail dress, midi length, in a rich fabric is equally correct. What does not belong is anything casual: cotton sundresses, jersey day dresses, flat sandals, a denim jacket.

If the invitation says black tie without the word optional, lean to the floor; our black tie wedding guest dresses guide covers that.

Length: gown, midi and the mini question

Floor length is the safest and the most formal, especially for an evening wedding, a gala and anything after six. A midi that falls to mid-calf works when the fabric carries the formality. A mini is the risky one. In a strongly embellished fabric at a party it can work, but for a wedding at this dress code we would not choose it.

Fabrics that read formal

Fabric does more than length to tell people you understood the brief. Satin, velvet, organza, lace and hand embellishment all read evening. Feathers do too, and a dark colour helps a midi feel formal. Matte jersey, linen and printed cotton read day, however long the hem.

Black tie optional dresses to shop

1. Malvina Feather Gown in Fig

New for Fall 2026: a feather gown in fig. The colour is rich enough for winter and the feathers do the work of jewellery.

2. Leanna Featherlike Organza Gown in Black

New for Holiday 2026, a black gown in featherlike organza. Black and floor length is the most reliable answer to this dress code.

3. Maril Knit Organza Midi Dress in Fig

Also new, a knit organza midi in fig. The midi option for guests who prefer not to wear a gown.

4. Zirelle Embellished Gown in Ink

An embellished Holiday 2026 gown in ink, the navy-adjacent colour that photographs well under evening light.

5. Reannon Draped Velvet Draped Gown in Goldenrod

A draped velvet gown in goldenrod, 80% viscose and 20% silk. Velvet is the winter fabric for formal dressing.

6. Thiora Velvet Embroidered Lace Midi Dress in Black

Black velvet with embroidered lace on a midi length, from Holiday 2026. Formal by fabric alone.

7. Joanna Off Shoulder Satin Midi Dress in Fig

An off-shoulder satin midi in fig, for a black tie optional event earlier in the evening.

8. Zoriel Embellished Halter Gown in Black

An embellished black halter gown from Holiday 2026, the cleanest neckline in the group.

How to choose a black tie optional dress

• Read the venue. A ballroom and an evening start point to a gown; a restaurant dinner allows a midi.
• Choose fabric first, then length. A velvet midi beats a jersey maxi.
• At a wedding, skip white and ivory unless the couple have asked for it.
• Plan your cover. A cape jacket keeps volume intact; see our cape jacket guide.
• Wear a heel you can stand in for four hours, and a small evening bag.

For seasonal versions, see winter wedding guest dresses and fall wedding guest dresses, and our evening dresses edit. For more gowns in this register, browse Jenny Packham, Safiyaa and Rasario.

Sizing for a formal dress

Gowns with a structured bodice need to fit at the bust; the skirt usually has room. SIMKHAI cuts dresses in US sizes, and its own chart sets US 00 as a UK 4, so a US 2 is a UK 8 and a US 6 is a UK 12. Tops, knitwear and outerwear run in letters from XS to XL. Most pieces fit true to size; read the fit note on each product page, and see our SIMKHAI size guide for the full table. Allow time for a tailor to take up a hem for the shoes you will wear.

Frequently asked questions

What does black tie optional mean for women?

It means dress as formally as for black tie, with a choice of length. A floor-length gown and an elegant, formal cocktail dress are both correct.

Can I wear a midi dress to a black tie optional wedding?

Yes, if the fabric is formal, such as satin, velvet, lace and embellishment. A casual midi in cotton and jersey is not right.

Can I wear a short dress to black tie optional?

It is risky. A heavily embellished mini can work at a party, but for a wedding a midi and a gown are safer.

What colours are best for a black tie optional event?

Black, deep jewel tones and rich neutrals all read evening. Avoid white and ivory at weddings unless the couple ask for it.

Is black tie optional more formal than cocktail attire?

Yes. Cocktail attire allows a knee-length dress; black tie optional expects a gown and a very formal midi.

Read next: Black tie wedding guest dresses, SIMKHAI gowns, Winter wedding guest dresses.

By Gemma Deeks, Coveti Fashion Editor. Updated 21 October 2026.