Wedding guest dress codes decoded: cocktail, semi-formal and more
For a wedding guest dress code, cocktail attire means a formal midi or shorter dress that does not touch the floor, with a structured silhouette, according to The Knot. It sits below formal and above semi-formal on that scale. This guide defines each code and matches LUNETTE (Lunette Woman) dresses to it.
How 2 sources define each code
Dress code labels are not standardized, so this guide reads 2 primary sources side by side: The Knot's wedding attire guide and the Emily Post Institute's attire guide (both retrieved 2026-10-17). Where they disagree, the table says so.
| Dress code | The Knot says (women's attire) | Emily Post says |
|---|---|---|
| White tie | Evening gowns, floor-length ball gowns, elbow-length white gloves | The most formal of all dress codes, with a floor-length evening gown |
| Black tie | Floor-length formal gowns, refined jewelry | A formal, floor-length evening gown |
| Black tie optional | Floor-length evening gowns or elevated midi dresses | A formal evening gown, a shorter cocktail dress, or dressy separates |
| Formal | Floor-length dresses, sleek jumpsuits, elegant cocktail dresses | No separate entry in the guide |
| Cocktail | Formal midi or shorter dresses that do not touch the floor, with structured silhouettes | Cocktail dress is listed under semi-formal and black tie optional |
| Semi-formal | Quietly elegant midi dresses, wrap dresses and jumpsuits, usually without heavy beading or sequins | A short afternoon or cocktail dress, a little black dress, or a long dressy skirt and top |
| Festive | Formalwear with sparkles, embellishments and statement silhouettes | Essentially cocktail party attire with a seasonal, holiday touch |
| Casual / daytime | Long sundresses or cheerful sundresses in nice fabrics | Clean, comfortable clothing; dressy casual sits between casual and formal |
| Beach / resort | Floral maxis and midis in breezy silhouettes; no formal gowns | Not covered |
Sources: The Knot, wedding dress codes and Emily Post, attire guide from casual to white tie. The notable disagreement is where cocktail dresses belong. The Knot ranks cocktail as its own step below formal. Emily Post folds the cocktail dress into semi-formal and into black tie optional. Emily Post also notes that for a semi-formal event later than 6 in the evening, you should err on the side of formality.
Dress code to LUNETTE piece
This matching is editorial judgment, not a store rule. LUNETTE does not label its dresses by wedding dress code, and the store does not stock tuxedo-formal gowns, so black tie and white tie have no match here. For those, buy from a formalwear retailer or rent.
| Code | Length and formality | LUNETTE pieces that fit |
|---|---|---|
| White tie, black tie | Floor-length formal gown | None. LUNETTE has no tuxedo-formal gowns. |
| Black tie optional, formal | Floor-length or elevated midi | High-Neck Halter Backless Satin Gown ($42.99) and Cowl Neck Slit Satin Maxi Dress ($28.99) in a dark shade, the closest options |
| Cocktail | Midi or knee length, dressy fabric | One-Shoulder Ruched Satin Slit Midi Dress ($35.99) and Halter Neck Satin A-Line Mini Dress ($43.99) |
| Semi-formal | Midi, quieter styling | Tie-Waist Round Neck Midi Dress ($45.99) and the Black option of the Spaghetti Strap Ruched Sweetheart Bodycon Midi Dress ($35.99) |
| Festive | Dressy with sparkle | Sweetheart Cutout Sequin Slit Maxi Dress ($44.99) and One-Shoulder Sequin Slit Maxi Dress ($52.99) |
| Garden, rustic, beach | Flowy maxi or midi | Halter Open-Knit Cutout Fringe Maxi Dress ($41.99) and Off-Shoulder Ombre Sheath Maxi Dress ($33.99) |
Cocktail attire
The Knot's description is a formal midi or shorter dress that does not touch the floor. The One-Shoulder Ruched Satin Slit Midi Dress comes in Black, Green and Brown, sizes S to XXL. The Halter Neck Satin A-Line Mini Dress is a short satin dress with a gathered halter neckline, offered in Bronze, sizes S to XL. A mini is the shortest end of cocktail, so for a conservative venue pick the midi.
Semi-formal
Both sources describe semi-formal as a step down in flash. The Knot specifically mentions quiet elegance in place of beading or sequins. The Tie-Waist Round Neck Midi Dress has a round neckline, a waist tie and elbow-length sleeves, in Light Blue and Navy Blue, sizes M to 2XL. Emily Post lists the little black dress here, so the Black spaghetti-strap midi works if you add a wrap or jacket for a ceremony.
Black tie optional
Emily Post says a formal gown, a shorter cocktail dress or dressy separates are all acceptable. The Knot says floor-length gowns or elevated midis. The 2 LUNETTE maxis listed above are the closest in length, and the High-Neck Halter Backless Satin Gown is a long satin halter gown with an open back and long ties. It is not a tuxedo-formal gown, so treat it as the casual end of black tie optional, in a dark color, with polished shoes and jewelry. If the invitation says black tie, skip it.
Festive, beach, garden and rustic
The Knot's festive code asks for sparkles and statement silhouettes. Both LUNETTE sequin maxis fit that brief. The Sweetheart Cutout Sequin Slit Maxi Dress comes in Black, Gold, Blue and Pink, sizes XS to L. For outdoor or resort weddings the Knot asks for breezy silhouettes that are not clingy, so the open-knit fringe maxi (Mustard, S to L) and the ombre maxi (Dark Red, Blue, Purple, Gray, S to 3XL) are better picks than the bodycon styles.
Practical notes before you buy
Check the sizes on the size guide against your measurements; LUNETTE sizes XS to XL are true to size and the store suggests sizing up if you are between sizes. The open-knit fringe maxi shows what is worn underneath, so choose your own base layer. Browse the full dresses collection if none of these fit the invitation.
FAQ
What is cocktail attire for a wedding?
A formal midi or shorter dress that does not touch the floor, with structure or shine, according to The Knot. Emily Post places the cocktail dress under semi-formal and black tie optional.
Can I wear a short dress to a black tie optional wedding?
Emily Post says a shorter cocktail dress is an accepted choice for black tie optional. The Knot leans toward floor-length gowns or elevated midis, so a midi is the safer length.
What is the difference between formal and semi-formal?
The Knot lists formal as floor-length dresses, sleek jumpsuits or elegant cocktail dresses, and semi-formal as quietly elegant midi dresses, wrap dresses and jumpsuits.
Does LUNETTE have black tie gowns?
No. LUNETTE has no tuxedo-formal gowns. Its longest dresses are maxis.
What if my size or length is wrong?
Returns are accepted within 14 days of delivery for unworn, unwashed items with tags attached. There is no direct exchange: you return the dress and reorder. Order well before the wedding date.
LUNETTE ships within the United States only. Standard delivery is 5 to 9 business days after 1 to 3 days of processing, and shipping is free over $60. LUNETTE has no reviews yet. Last reviewed 2026-10-17.