For women, black-tie dress code expectations are floor-length evening gowns. While you can go with a more subdued or evening-appropriate color, your evening dress at a black-tie wedding doesn't have to be black. For those who prefer not to wear dresses, a formal jumpsuit in a dark hue or a women's tuxedo would be appropriate.
For men, the black tie dress code means a traditional tux is the way to go. You can expect that the wedding party and male guests will be wearing tuxedos at a black tie event. This usually consists of a black or midnight blue dinner jacket with matching trousers, a white tuxedo shirt with French cuffs, and a black bow tie.