Considering all seasons, venues, size ranges, and personal tastes, we researched the best black-tie wedding guest dresses and fell in love with several styles you need for your next formal celebration. Despite existing to help guests know what to wear, wedding dress codes can stress out some wedding attendees who are fearful they'll show up in the wrong attire. This is especially true of black-tie wedding dress codes . Size Range: 00-18 | Materials: PolyesterBest Black-Tie Wedding Guest Dress for a Summer Wedding Reformation Kastoria Dress Credit: Reformation View on Reformation Boasting a sophisticated structure with a pretty, whimsical print, this is perfect for a summer wedding with a black-tie dress code. Size Range: 12-24 | Materials: PolyesterBest Black-Tie Wedding Guest Dress With Scarf Reformation Oren Silk Dress Es Credit: Reformation View on Reformation We love this Reformation gown for its effortless sophistication.