Clothing along the lines of business casual would be most appropriate. For women, skirts, blouses, pant suits and casual dresses; for the men, slacks and a collared shirt are fine. For both men and women, tailored jeans in good condition may be acceptable at most performances. Nice casual business shoes or dress shoes are also a good idea. Leave the sneakers and Birkenstock’s for going to the movies. Most importantly, you need to be comfortable in your attire while still showing respect for the performers and your surroundings.
Children should be dressed neatly, no matter what they’re wearing. For girls, a comfortable jumper or dress with tights is akin to a kid's version of business casual and boys should wear a collared polo shirt and khakis or tidy looking jeans. Teen boys should similarly wear a collared polo shirt and nice slacks with loafers or dress shoes, while teenage girls, who often like to preen and be seen can wear a nice casual dress with tights like their smaller counterparts.
Holiday performances of “The Nutcracker” are usually children’s introduction to ballet and a special event for the whole family. At these times, you will probably see adults and their children in their best clothes for photos and for separating the ballet as a special activity.
Local productions usually would accept a more casual dress code than larger traveling companies in prestigious venues. However, even if you’re attending a fancy traveling company doing a well known showcase ballet, you should still dress comfortably. The Joffrey Ballet in Chicago, for example, recommends business casual on their website, which they define as coats and ties for men and dresses or skirts for women.The New York City Ballet’s website asserts that jeans are perfectly fine and warn not to dress up unless you’re going to a performance of “The Nutcracker.” The Royal Opera House in London claims that you can wear jeans, although most people don’t, or you can wear evening gowns and some people do. The best solution would be to check with the website of the theater you’ll be attending for a glimpse into their local dress culture.