Black Tie Optional Dress Code Guide

Black tie optional is a dress code that invites formal evening dress while formally permitting a step down: a tuxedo is welcomed but not required for men, and a floor-length gown is welcomed but not required for women. In practice it means the hosts expect an elegant evening — weddings, galas, charity balls and formal holiday parties — and are telling guests that a dark suit or a dressy cocktail dress, worn well, will not look out of place. It is one of the most common dress codes on American wedding invitations, and one of the most misread.

Black tie optional sits on the dress-code ladder one rung below black tie and well above semi-formal. The word 'optional' refers only to the tuxedo and the gown — it is never an invitation to dress casually. This guide explains what women and men should wear, what to avoid, and how the code compares with its neighbours. For the full rig in detail, see our men's black tie guide; for how the code is used at weddings, see the wedding guest attire hub.

For Women: Gowns, Long Dresses and Dressy Cocktail Dresses

A floor-length evening gown is always correct at black tie optional, and it is the safest choice when the venue is grand or the event is a wedding where the couple have dressed formally. Choose evening fabrics — crepe, satin, chiffon, velvet, or beaded and sequinned cloth — in deep or rich colours; black is entirely acceptable for guests at evening events. A gown with a train is more than the code asks for; a clean, sweeping hem is the mark to hit.

A dressy cocktail dress is the sanctioned alternative: knee-length to midi, in an unmistakably evening fabric, styled with heels, evening jewellery and a clutch rather than a daytime bag. A tailored evening jumpsuit or a dressy pantsuit in satin or crepe also passes, which is why mothers of the couple often choose them — see our mother of the bride guide and mother of the groom guide. What does not pass: sundresses, cotton or jersey day dresses, daytime prints, and anything you would wear to a garden lunch.

For Men: Tuxedo Welcome, Dark Suit Fully Acceptable

Wear the tuxedo if you own one or enjoy wearing one — at black tie optional you will not be overdressed, because a share of the room will be in black tie. The classic rig is a black or midnight-blue dinner jacket with satin lapels, matching trousers with a satin stripe, a white dress shirt, a black bow tie, and polished black shoes. Our men's black tie guide covers the details, from studs and cummerbunds to the shoes that finish it.

The dark suit is the code's built-in alternative and carries no apology: black, charcoal or very dark navy, worn with a white dress shirt, a conservative dark tie (a bow tie is not worn with a suit), a pocket square if you like, and well-polished black dress shoes. Keep the suit tailored and the shirt crisp — at this level of formality, fit and polish are what separate 'dark suit' from 'business suit'. A light-coloured suit, a blazer with odd trousers, or a suit worn without a tie all fall below the code.

What to Avoid — and How Black Tie Optional Compares

Avoid anything that reads as daytime or casual: light suits, khakis, loafers without socks, short or casual dresses, denim in any form, and novelty ties or loud party shirts. Also avoid out-dressing the hosts in the other direction — a white dinner jacket out of season, a tailcoat, or a ball gown with a full train belongs to stricter codes. When in doubt, err slightly formal: nobody remembers the guest who was a touch too elegant.

The ladder, from the top: black tie requires the tuxedo and expects gowns. Black tie optional invites both but formally accepts the dark suit and the dressy cocktail dress. Semi-formal drops another clear step — suits in any sober colour and cocktail dresses as the standard, no tuxedo expected. Below that sit festive attire and dressy casual, the polished end of casual. If an invitation says black tie optional, dress for the second rung and you will match the room.